Commit Graph

473 Commits

Author SHA1 Message Date
Oleg Nesterov
b1442b055c reparent_thread: fix the "is it traced" check
reparent_thread() uses ptrace_reparented() to check whether this thread is
ptraced, in that case we should not notify the new parent.

But ptrace_reparented() is not exactly correct when the reparented thread
is traced by /sbin/init, because forget_original_parent() has already
changed ->real_parent.

Currently, the only problem is the false notification.  But with the next
patch the kernel crash in this (yes, pathological) case.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:59 -07:00
Oleg Nesterov
0a967a044a reparent_thread: don't call kill_orphaned_pgrp() if task_detached()
If task_detached(p) == T, then either

  a) p is not the main thread, we will find the group leader on the
     ->children list.

or

  b) p is the group leader but its ->exit_state = EXIT_DEAD.  This
     can only happen when the last sub-thread has died, but in that case
     that thread has already called kill_orphaned_pgrp() from
     exit_notify().

In both cases kill_orphaned_pgrp() looks bogus.

Move the task_detached() check up and simplify the code, this is also
right from the "common sense" pov: we should do nothing with the detached
childs, except move them to the new parent's ->children list.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:59 -07:00
Oleg Nesterov
b1b4c6799f ptrace: reintroduce __ptrace_detach() as a callee of ptrace_exit()
No functional changes, preparation for the next patch.

Move the "should we release this child" logic into the separate handler,
__ptrace_detach().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:59 -07:00
Oleg Nesterov
6d69cb87f0 ptrace: simplify ptrace_exit()->ignoring_children() path
ignoring_children() takes parent->sighand->siglock and checks
k_sigaction[SIGCHLD] atomically.  But this buys nothing, we can't get the
"really" wrong result even if we race with sigaction(SIGCHLD).  If we read
the "stale" sa_handler/sa_flags we can pretend it was changed right after
the check.

Remove spin_lock(->siglock), and kill "int ign" which caches the result of
ignoring_children() which becomes rather trivial.

Perhaps it makes sense to export this helper, do_notify_parent() can use
it too.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:59 -07:00
Oleg Nesterov
90bc8d8b1a do_wait: fix waiting for the group stop with the dead leader
do_wait(WSTOPPED) assumes that p->state must be == TASK_STOPPED, this is
not true if the leader is already dead.  Check SIGNAL_STOP_STOPPED instead
and use signal->group_exit_code.

Trivial test-case:

	void *tfunc(void *arg)
	{
		pause();
		return NULL;
	}

	int main(void)
	{
		pthread_t thr;
		pthread_create(&thr, NULL, tfunc, NULL);
		pthread_exit(NULL);
		return 0;
	}

It doesn't react to ^Z (and then to ^C or ^\). The task is stopped, but
bash can't see this.

The bug is very old, and it was reported multiple times. This patch was sent
more than a year ago (http://marc.info/?t=119713920000003) but it was ignored.

This change also fixes other oddities (but not all) in this area.  For
example, before this patch:

	$ sleep 100
	^Z
	[1]+  Stopped                 sleep 100
	$ strace -p `pidof sleep`
	Process 11442 attached - interrupt to quit

strace hangs in do_wait(), because ->exit_code was already consumed by
bash.  After this patch, strace happily proceeds:

	--- SIGTSTP (Stopped) @ 0 (0) ---
	restart_syscall(<... resuming interrupted call ...>

To me, this looks much more "natural" and correct.

Another example.  Let's suppose we have the main thread M and sub-thread
T, the process is stopped, and its parent did wait(WSTOPPED).  Now we can
ptrace T but not M.  This looks at least strange to me.

Imho, do_wait() should not confuse the per-thread ptrace stops with the
per-process job control stops.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Kaz Kylheku <kkylheku@gmail.com>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:57 -07:00
Al Viro
5ad4e53bd5 Get rid of indirect include of fs_struct.h
Don't pull it in sched.h; very few files actually need it and those
can include directly.  sched.h itself only needs forward declaration
of struct fs_struct;

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-31 23:00:27 -04:00
Al Viro
3e93cd6718 Take fs_struct handling to new file (fs/fs_struct.c)
Pure code move; two new helper functions for nfsd and daemonize
(unshare_fs_struct() and daemonize_fs_struct() resp.; for now -
the same code as used to be in callers).  unshare_fs_struct()
exported (for nfsd, as copy_fs_struct()/exit_fs() used to be),
copy_fs_struct() and exit_fs() don't need exports anymore.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-31 23:00:26 -04:00
Thomas Gleixner
3aa551c9b4 genirq: add threaded interrupt handler support
Add support for threaded interrupt handlers:

A device driver can request that its main interrupt handler runs in a
thread. To achive this the device driver requests the interrupt with
request_threaded_irq() and provides additionally to the handler a
thread function. The handler function is called in hard interrupt
context and needs to check whether the interrupt originated from the
device. If the interrupt originated from the device then the handler
can either return IRQ_HANDLED or IRQ_WAKE_THREAD. IRQ_HANDLED is
returned when no further action is required. IRQ_WAKE_THREAD causes
the genirq code to invoke the threaded (main) handler. When
IRQ_WAKE_THREAD is returned handler must have disabled the interrupt
on the device level. This is mandatory for shared interrupt handlers,
but we need to do it as well for obscure x86 hardware where disabling
an interrupt on the IO_APIC level redirects the interrupt to the
legacy PIC interrupt lines.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
2009-03-24 12:15:23 +01:00
Ingo Molnar
f8a6b2b9ce Merge branch 'linus' into x86/apic
Conflicts:
	arch/x86/kernel/acpi/boot.c
	arch/x86/mm/fault.c
2009-02-13 09:44:22 +01:00
Ingo Molnar
e9c4ffb11f Merge branch 'linus' into perfcounters/core
Conflicts:
	arch/x86/kernel/acpi/boot.c
2009-02-13 09:34:07 +01:00
Peter Zijlstra
32bd671d6c signal: re-add dead task accumulation stats.
We're going to split the process wide cpu accounting into two parts:

 - clocks; which can take all the time they want since they run
           from user context.

 - timers; which need constant time tracing but can affort the overhead
           because they're default off -- and rare.

The clock readout will go back to a full sum of the thread group, for this
we need to re-add the exit stats that were removed in the initial itimer
rework (f06febc9: timers: fix itimer/many thread hang).

Furthermore, since that full sum can be rather slow for large thread groups
and we have the complete dead task stats, revert the do_notify_parent time
computation.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 13:04:33 +01:00
Ingo Molnar
bfe2a3c3b5 Merge branch 'core/percpu' into perfcounters/core
Conflicts:
	arch/x86/include/asm/hardirq_32.h
	arch/x86/include/asm/hardirq_64.h

Semantic merge:
	arch/x86/include/asm/hardirq.h
	[ added apic_perf_irqs field. ]

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-23 10:20:15 +01:00
Ingo Molnar
77835492ed Merge commit 'v2.6.29-rc2' into perfcounters/core
Conflicts:
	include/linux/syscalls.h
2009-01-21 16:37:27 +01:00
Ingo Molnar
198030782c Merge branch 'x86/mm' into core/percpu
Conflicts:
	arch/x86/mm/fault.c
2009-01-21 10:39:51 +01:00
Ingo Molnar
b2b062b816 Merge branch 'core/percpu' into stackprotector
Conflicts:
	arch/x86/include/asm/pda.h
	arch/x86/include/asm/system.h

Also, moved include/asm-x86/stackprotector.h to arch/x86/include/asm.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-18 18:37:14 +01:00
Heiko Carstens
17da2bd90a [CVE-2009-0029] System call wrappers part 08
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:21 +01:00
Heiko Carstens
754fe8d297 [CVE-2009-0029] System call wrappers part 07
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:20 +01:00
Heiko Carstens
2ed7c03ec1 [CVE-2009-0029] Convert all system calls to return a long
Convert all system calls to return a long. This should be a NOP since all
converted types should have the same size anyway.
With the exception of sys_exit_group which returned void. But that doesn't
matter since the system call doesn't return.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:14 +01:00
Ingo Molnar
506c10f26c Merge commit 'v2.6.29-rc1' into perfcounters/core
Conflicts:
	include/linux/kernel_stat.h
2009-01-11 02:42:53 +01:00
Oleg Nesterov
901608d904 mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting
xacct_add_tsk() relies on do_exit()->update_hiwater_xxx() and uses
mm->hiwater_xxx directly, this leads to 2 problems:

- taskstats_user_cmd() can call fill_pid()->xacct_add_tsk() at any
  moment before the task exits, so we should check the current values of
  rss/vm anyway.

- do_exit()->update_hiwater_xxx() calls are racy.  An exiting thread can
  be preempted right before mm->hiwater_xxx = new_val, and another thread
  can use A_LOT of memory and exit in between.  When the first thread
  resumes it can be the last thread in the thread group, in that case we
  report the wrong hiwater_xxx values which do not take A_LOT into
  account.

Introduce get_mm_hiwater_rss() and get_mm_hiwater_vm() helpers and change
xacct_add_tsk() to use them.  The first helper will also be used by
rusage->ru_maxrss accounting.

Kill do_exit()->update_hiwater_xxx() calls.  Unless we are going to
decrease rss/vm there is no point to update mm->hiwater_xxx, and nobody
can look at this mm_struct when exit_mmap() actually unmaps the memory.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:09 -08:00
Hugh Dickins
e5991371ee mm: remove cgroup_mm_owner_callbacks
cgroup_mm_owner_callbacks() was brought in to support the memrlimit
controller, but sneaked into mainline ahead of it.  That controller has
now been shelved, and the mm_owner_changed() args were inadequate for it
anyway (they needed an mm pointer instead of a task pointer).

Remove the dead code, and restore mm_update_next_owner() locking to how it
was before: taking mmap_sem there does nothing for memcontrol.c, now the
only user of mm->owner.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:01 -08:00
Ingo Molnar
a9de18eb76 Merge branch 'linus' into stackprotector
Conflicts:
	arch/x86/include/asm/pda.h
	kernel/fork.c
2008-12-31 08:31:57 +01:00
Linus Torvalds
1dff81f20c Merge branch 'for-2.6.29' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.29' of git://git.kernel.dk/linux-2.6-block: (43 commits)
  bio: get rid of bio_vec clearing
  bounce: don't rely on a zeroed bio_vec list
  cciss: simplify parameters to deregister_disk function
  cfq-iosched: fix race between exiting queue and exiting task
  loop: Do not call loop_unplug for not configured loop device.
  loop: Flush possible running bios when loop device is released.
  alpha: remove dead BIO_VMERGE_BOUNDARY
  Get rid of CONFIG_LSF
  block: make blk_softirq_init() static
  block: use min_not_zero in blk_queue_stack_limits
  block: add one-hit cache for disk partition lookup
  cfq-iosched: remove limit of dispatch depth of max 4 times quantum
  nbd: tell the block layer that it is not a rotational device
  block: get rid of elevator_t typedef
  aio: make the lookup_ioctx() lockless
  bio: add support for inlining a number of bio_vecs inside the bio
  bio: allow individual slabs in the bio_set
  bio: move the slab pointer inside the bio_set
  bio: only mempool back the largest bio_vec slab cache
  block: don't use plugging on SSD devices
  ...
2008-12-30 17:20:05 -08:00
Linus Torvalds
5f34fe1cfc Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits)
  stacktrace: provide save_stack_trace_tsk() weak alias
  rcu: provide RCU options on non-preempt architectures too
  printk: fix discarding message when recursion_bug
  futex: clean up futex_(un)lock_pi fault handling
  "Tree RCU": scalable classic RCU implementation
  futex: rename field in futex_q to clarify single waiter semantics
  x86/swiotlb: add default swiotlb_arch_range_needs_mapping
  x86/swiotlb: add default phys<->bus conversion
  x86: unify pci iommu setup and allow swiotlb to compile for 32 bit
  x86: add swiotlb allocation functions
  swiotlb: consolidate swiotlb info message printing
  swiotlb: support bouncing of HighMem pages
  swiotlb: factor out copy to/from device
  swiotlb: add arch hook to force mapping
  swiotlb: allow architectures to override phys<->bus<->phys conversions
  swiotlb: add comment where we handle the overflow of a dma mask on 32 bit
  rcu: fix rcutorture behavior during reboot
  resources: skip sanity check of busy resources
  swiotlb: move some definitions to header
  swiotlb: allow architectures to override swiotlb pool allocation
  ...

Fix up trivial conflicts in
  arch/x86/kernel/Makefile
  arch/x86/mm/init_32.c
  include/linux/hardirq.h
as per Ingo's suggestions.
2008-12-30 16:10:19 -08:00
Ingo Molnar
e1df957670 Merge branch 'linus' into perfcounters/core
Conflicts:
	fs/exec.c
	include/linux/init_task.h

Simple context conflicts.
2008-12-29 09:45:15 +01:00
Nikanth Karthikesan
7c0990c7ee Do not free io context when taking recursive faults in do_exit
When taking recursive faults in do_exit, if the io_context is not null,
exit_io_context() is being called. But it might decrement the refcount
more than once. It is better to leave this task alone.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:28:43 +01:00
Linus Torvalds
b0f4b285d7 Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (241 commits)
  sched, trace: update trace_sched_wakeup()
  tracing/ftrace: don't trace on early stage of a secondary cpu boot, v3
  Revert "x86: disable X86_PTRACE_BTS"
  ring-buffer: prevent false positive warning
  ring-buffer: fix dangling commit race
  ftrace: enable format arguments checking
  x86, bts: memory accounting
  x86, bts: add fork and exit handling
  ftrace: introduce tracing_reset_online_cpus() helper
  tracing: fix warnings in kernel/trace/trace_sched_switch.c
  tracing: fix warning in kernel/trace/trace.c
  tracing/ring-buffer: remove unused ring_buffer size
  trace: fix task state printout
  ftrace: add not to regex on filtering functions
  trace: better use of stack_trace_enabled for boot up code
  trace: add a way to enable or disable the stack tracer
  x86: entry_64 - introduce FTRACE_ frame macro v2
  tracing/ftrace: add the printk-msg-only option
  tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp()
  x86, bts: correctly report invalid bts records
  ...

Fixed up trivial conflict in scripts/recordmcount.pl due to SH bits
being already partly merged by the SH merge.
2008-12-28 12:21:10 -08:00
Ingo Molnar
eef6cbf584 perfcounters: pull inherited counters
Change counter inheritance from a 'push' to a 'pull' model: instead of
child tasks pushing their final counts to the parent, reuse the wait4
infrastructure to pull counters as child tasks are exit-processed,
much like how cutime/cstime is collected.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-23 12:45:16 +01:00
Ingo Molnar
aa9c4c0f96 perfcounters: fix task clock counter
Impact: fix per task clock counter precision

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-23 12:45:14 +01:00
Ingo Molnar
9b51f66dcb perfcounters: implement "counter inheritance"
Impact: implement new performance feature

Counter inheritance can be used to run performance counters in a workload,
transparently - and pipe back the counter results to the parent counter.

Inheritance for performance counters works the following way: when creating
a counter it can be marked with the .inherit=1 flag. Such counters are then
'inherited' by all child tasks (be they fork()-ed or clone()-ed). These
counters get inherited through exec() boundaries as well (except through
setuid boundaries).

The counter values get added back to the parent counter(s) when the child
task(s) exit - much like stime/utime statistics are gathered. So inherited
counters are ideal to gather summary statistics about an application's
behavior via shell commands, without having to modify that application.

The timec.c command utilizes counter inheritance:

  http://redhat.com/~mingo/perfcounters/timec.c

Sample output:

   $ ./timec -e 1 -e 3 -e 5 ls -lR /usr/include/ >/dev/null

   Performance counter stats for 'ls':

           163516953 instructions
                2295 cache-misses
             2855182 branch-misses

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-14 20:30:49 +01:00
Ingo Molnar
b19b3c74c7 Merge branches 'core/debug', 'core/futexes', 'core/locking', 'core/rcu', 'core/signal', 'core/urgent' and 'core/xen' into core/core 2008-11-24 17:44:55 +01:00
Frederic Weisbecker
65afa5e603 tracing/function-return-tracer: free the return stack on free_task()
Impact: avoid losing some traces when a task is freed

do_exit() is not the last function called when a task finishes.
There are still some functions which are to be called such as
ree_task().  So we delay the freeing of the return stack to the
last moment.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23 22:34:02 +01:00
Ingo Molnar
82f60f0bc8 tracing/function-return-tracer: clean up task start/exit callbacks
Impact: cleanup

Eliminate #ifdefs in core code by using empty inline functions.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23 09:19:35 +01:00
Frederic Weisbecker
f201ae2356 tracing/function-return-tracer: store return stack into task_struct and allocate it dynamically
Impact: use deeper function tracing depth safely

Some tests showed that function return tracing needed a more deeper depth
of function calls. But it could be unsafe to store these return addresses
to the stack.

So these arrays will now be allocated dynamically into task_struct of current
only when the tracer is activated.

Typical scheme when tracer is activated:
- allocate a return stack for each task in global list.
- fork: allocate the return stack for the newly created task
- exit: free return stack of current
- idle init: same as fork

I chose a default depth of 50. I don't have overruns anymore.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23 09:17:26 +01:00
Ingo Molnar
9676e73a9e Merge branches 'tracing/ftrace' and 'tracing/urgent' into tracing/core
Conflicts:
	kernel/trace/ftrace.c

[ We conflicted here because we backported a few fixes to
  tracing/urgent - which has different internal APIs. ]
2008-11-19 10:04:25 +01:00
James Morris
f3a5c54701 Merge branch 'master' into next
Conflicts:
	fs/cifs/misc.c

Merge to resolve above, per the patch below.

Signed-off-by: James Morris <jmorris@namei.org>

diff --cc fs/cifs/misc.c
index ec36410,addd1dc..0000000
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@@ -347,13 -338,13 +338,13 @@@ header_assemble(struct smb_hdr *buffer
  		/*  BB Add support for establishing new tCon and SMB Session  */
  		/*      with userid/password pairs found on the smb session   */
  		/*	for other target tcp/ip addresses 		BB    */
 -				if (current->fsuid != treeCon->ses->linux_uid) {
 +				if (current_fsuid() != treeCon->ses->linux_uid) {
  					cFYI(1, ("Multiuser mode and UID "
  						 "did not match tcon uid"));
- 					read_lock(&GlobalSMBSeslock);
- 					list_for_each(temp_item, &GlobalSMBSessionList) {
- 						ses = list_entry(temp_item, struct cifsSesInfo, cifsSessionList);
+ 					read_lock(&cifs_tcp_ses_lock);
+ 					list_for_each(temp_item, &treeCon->ses->server->smb_ses_list) {
+ 						ses = list_entry(temp_item, struct cifsSesInfo, smb_ses_list);
 -						if (ses->linux_uid == current->fsuid) {
 +						if (ses->linux_uid == current_fsuid()) {
  							if (ses->server == treeCon->ses->server) {
  								cFYI(1, ("found matching uid substitute right smb_uid"));
  								buffer->Uid = ses->Suid;
2008-11-18 18:52:37 +11:00
Oleg Nesterov
2b5fe6de58 thread_group_cputime: move a couple of callsites outside of ->siglock
Impact: relax the locking of cpu-time accounting calls

->siglock buys nothing for thread_group_cputime() in do_sys_times() and
wait_task_zombie() (which btw takes the unrelated parent's ->siglock).

Actually I think do_sys_times() doesn't need ->siglock at all.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-17 16:55:55 +01:00
Mathieu Desnoyers
7e066fb870 tracepoints: add DECLARE_TRACE() and DEFINE_TRACE()
Impact: API *CHANGE*. Must update all tracepoint users.

Add DEFINE_TRACE() to tracepoints to let them declare the tracepoint
structure in a single spot for all the kernel. It helps reducing memory
consumption, especially when declaring a lot of tracepoints, e.g. for
kmalloc tracing.

*API CHANGE WARNING*: now, DECLARE_TRACE() must be used in headers for
tracepoint declarations rather than DEFINE_TRACE(). This is the sane way
to do it. The name previously used was misleading.

Updates scheduler instrumentation to follow this API change.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 09:01:36 +01:00
Linus Torvalds
8141c7f3e7 Move "exit_robust_list" into mm_release()
We don't want to get rid of the futexes just at exit() time, we want to
drop them when doing an execve() too, since that gets rid of the
previous VM image too.

Doing it at mm_release() time means that we automatically always do it
when we disassociate a VM map from the task.

Reported-by: pageexec@freemail.hu
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Alex Efros <powerman@powerman.name>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-15 10:20:36 -08:00
James Morris
2b82892565 Merge branch 'master' into next
Conflicts:
	security/keys/internal.h
	security/keys/process_keys.c
	security/keys/request_key.c

Fixed conflicts above by using the non 'tsk' versions.

Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 11:29:12 +11:00
David Howells
d84f4f992c CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management.  This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.

A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().

With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:

	struct cred *new = prepare_creds();
	int ret = blah(new);
	if (ret < 0) {
		abort_creds(new);
		return ret;
	}
	return commit_creds(new);

There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.

To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const.  The purpose of this is compile-time
discouragement of altering credentials through those pointers.  Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:

  (1) Its reference count may incremented and decremented.

  (2) The keyrings to which it points may be modified, but not replaced.

The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).

This patch and the preceding patches have been tested with the LTP SELinux
testsuite.

This patch makes several logical sets of alteration:

 (1) execve().

     This now prepares and commits credentials in various places in the
     security code rather than altering the current creds directly.

 (2) Temporary credential overrides.

     do_coredump() and sys_faccessat() now prepare their own credentials and
     temporarily override the ones currently on the acting thread, whilst
     preventing interference from other threads by holding cred_replace_mutex
     on the thread being dumped.

     This will be replaced in a future patch by something that hands down the
     credentials directly to the functions being called, rather than altering
     the task's objective credentials.

 (3) LSM interface.

     A number of functions have been changed, added or removed:

     (*) security_capset_check(), ->capset_check()
     (*) security_capset_set(), ->capset_set()

     	 Removed in favour of security_capset().

     (*) security_capset(), ->capset()

     	 New.  This is passed a pointer to the new creds, a pointer to the old
     	 creds and the proposed capability sets.  It should fill in the new
     	 creds or return an error.  All pointers, barring the pointer to the
     	 new creds, are now const.

     (*) security_bprm_apply_creds(), ->bprm_apply_creds()

     	 Changed; now returns a value, which will cause the process to be
     	 killed if it's an error.

     (*) security_task_alloc(), ->task_alloc_security()

     	 Removed in favour of security_prepare_creds().

     (*) security_cred_free(), ->cred_free()

     	 New.  Free security data attached to cred->security.

     (*) security_prepare_creds(), ->cred_prepare()

     	 New. Duplicate any security data attached to cred->security.

     (*) security_commit_creds(), ->cred_commit()

     	 New. Apply any security effects for the upcoming installation of new
     	 security by commit_creds().

     (*) security_task_post_setuid(), ->task_post_setuid()

     	 Removed in favour of security_task_fix_setuid().

     (*) security_task_fix_setuid(), ->task_fix_setuid()

     	 Fix up the proposed new credentials for setuid().  This is used by
     	 cap_set_fix_setuid() to implicitly adjust capabilities in line with
     	 setuid() changes.  Changes are made to the new credentials, rather
     	 than the task itself as in security_task_post_setuid().

     (*) security_task_reparent_to_init(), ->task_reparent_to_init()

     	 Removed.  Instead the task being reparented to init is referred
     	 directly to init's credentials.

	 NOTE!  This results in the loss of some state: SELinux's osid no
	 longer records the sid of the thread that forked it.

     (*) security_key_alloc(), ->key_alloc()
     (*) security_key_permission(), ->key_permission()

     	 Changed.  These now take cred pointers rather than task pointers to
     	 refer to the security context.

 (4) sys_capset().

     This has been simplified and uses less locking.  The LSM functions it
     calls have been merged.

 (5) reparent_to_kthreadd().

     This gives the current thread the same credentials as init by simply using
     commit_thread() to point that way.

 (6) __sigqueue_alloc() and switch_uid()

     __sigqueue_alloc() can't stop the target task from changing its creds
     beneath it, so this function gets a reference to the currently applicable
     user_struct which it then passes into the sigqueue struct it returns if
     successful.

     switch_uid() is now called from commit_creds(), and possibly should be
     folded into that.  commit_creds() should take care of protecting
     __sigqueue_alloc().

 (7) [sg]et[ug]id() and co and [sg]et_current_groups.

     The set functions now all use prepare_creds(), commit_creds() and
     abort_creds() to build and check a new set of credentials before applying
     it.

     security_task_set[ug]id() is called inside the prepared section.  This
     guarantees that nothing else will affect the creds until we've finished.

     The calling of set_dumpable() has been moved into commit_creds().

     Much of the functionality of set_user() has been moved into
     commit_creds().

     The get functions all simply access the data directly.

 (8) security_task_prctl() and cap_task_prctl().

     security_task_prctl() has been modified to return -ENOSYS if it doesn't
     want to handle a function, or otherwise return the return value directly
     rather than through an argument.

     Additionally, cap_task_prctl() now prepares a new set of credentials, even
     if it doesn't end up using it.

 (9) Keyrings.

     A number of changes have been made to the keyrings code:

     (a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
     	 all been dropped and built in to the credentials functions directly.
     	 They may want separating out again later.

     (b) key_alloc() and search_process_keyrings() now take a cred pointer
     	 rather than a task pointer to specify the security context.

     (c) copy_creds() gives a new thread within the same thread group a new
     	 thread keyring if its parent had one, otherwise it discards the thread
     	 keyring.

     (d) The authorisation key now points directly to the credentials to extend
     	 the search into rather pointing to the task that carries them.

     (e) Installing thread, process or session keyrings causes a new set of
     	 credentials to be created, even though it's not strictly necessary for
     	 process or session keyrings (they're shared).

(10) Usermode helper.

     The usermode helper code now carries a cred struct pointer in its
     subprocess_info struct instead of a new session keyring pointer.  This set
     of credentials is derived from init_cred and installed on the new process
     after it has been cloned.

     call_usermodehelper_setup() allocates the new credentials and
     call_usermodehelper_freeinfo() discards them if they haven't been used.  A
     special cred function (prepare_usermodeinfo_creds()) is provided
     specifically for call_usermodehelper_setup() to call.

     call_usermodehelper_setkeys() adjusts the credentials to sport the
     supplied keyring as the new session keyring.

(11) SELinux.

     SELinux has a number of changes, in addition to those to support the LSM
     interface changes mentioned above:

     (a) selinux_setprocattr() no longer does its check for whether the
     	 current ptracer can access processes with the new SID inside the lock
     	 that covers getting the ptracer's SID.  Whilst this lock ensures that
     	 the check is done with the ptracer pinned, the result is only valid
     	 until the lock is released, so there's no point doing it inside the
     	 lock.

(12) is_single_threaded().

     This function has been extracted from selinux_setprocattr() and put into
     a file of its own in the lib/ directory as join_session_keyring() now
     wants to use it too.

     The code in SELinux just checked to see whether a task shared mm_structs
     with other tasks (CLONE_VM), but that isn't good enough.  We really want
     to know if they're part of the same thread group (CLONE_THREAD).

(13) nfsd.

     The NFS server daemon now has to use the COW credentials to set the
     credentials it is going to use.  It really needs to pass the credentials
     down to the functions it calls, but it can't do that until other patches
     in this series have been applied.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:23 +11:00
David Howells
c69e8d9c01 CRED: Use RCU to access another task's creds and to release a task's own creds
Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:19 +11:00
David Howells
b6dff3ec5e CRED: Separate task security context from task_struct
Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:16 +11:00
Oleg Nesterov
ad474caca3 fix for account_group_exec_runtime(), make sure ->signal can't be freed under rq->lock
Impact: fix hang/crash on ia64 under high load

This is ugly, but the simplest patch by far.

Unlike other similar routines, account_group_exec_runtime() could be
called "implicitly" from within scheduler after exit_notify(). This
means we can race with the parent doing release_task(), we can't just
check ->signal != NULL.

Change __exit_signal() to do spin_unlock_wait(&task_rq(tsk)->lock)
before __cleanup_signal() to make sure ->signal can't be freed under
task_rq(tsk)->lock. Note that task_rq_unlock_wait() doesn't care
about the case when tsk changes cpu/rq under us, this should be OK.

Thanks to Ingo who nacked my previous buggy patch.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reported-by: Doug Chapman <doug.chapman@hp.com>
2008-11-11 08:01:43 +01:00
Linus Torvalds
92b29b86fe Merge branch 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (131 commits)
  tracing/fastboot: improve help text
  tracing/stacktrace: improve help text
  tracing/fastboot: fix initcalls disposition in bootgraph.pl
  tracing/fastboot: fix bootgraph.pl initcall name regexp
  tracing/fastboot: fix issues and improve output of bootgraph.pl
  tracepoints: synchronize unregister static inline
  tracepoints: tracepoint_synchronize_unregister()
  ftrace: make ftrace_test_p6nop disassembler-friendly
  markers: fix synchronize marker unregister static inline
  tracing/fastboot: add better resolution to initcall debug/tracing
  trace: add build-time check to avoid overrunning hex buffer
  ftrace: fix hex output mode of ftrace
  tracing/fastboot: fix initcalls disposition in bootgraph.pl
  tracing/fastboot: fix printk format typo in boot tracer
  ftrace: return an error when setting a nonexistent tracer
  ftrace: make some tracers reentrant
  ring-buffer: make reentrant
  ring-buffer: move page indexes into page headers
  tracing/fastboot: only trace non-module initcalls
  ftrace: move pc counter in irqtrace
  ...

Manually fix conflicts:
 - init/main.c: initcall tracing
 - kernel/module.c: verbose level vs tracepoints
 - scripts/bootgraph.pl: fallout from cherry-picking commits.
2008-10-20 13:35:07 -07:00
Thomas Gleixner
c465a76af6 Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', 'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus 2008-10-20 13:14:06 +02:00
Balbir Singh
9363b9f23c memrlimit: cgroup mm owner callback changes to add task info
This patch adds an additional field to the mm_owner callbacks. This field
is required to get to the mm that changed. Hold mmap_sem in write mode
before calling the mm_owner_changed callback

[hugh@veritas.com: fix mmap_sem deadlock]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 11:21:28 -07:00
Ingo Molnar
b2aaf8f74c Merge branch 'linus' into stackprotector
Conflicts:
	arch/x86/kernel/Makefile
	include/asm-x86/pda.h
2008-10-15 13:46:29 +02:00
Mathieu Desnoyers
0a16b60758 tracing, sched: LTTng instrumentation - scheduler
Instrument the scheduler activity (sched_switch, migration, wakeups,
wait for a task, signal delivery) and process/thread
creation/destruction (fork, exit, kthread stop). Actually, kthread
creation is not instrumented in this patch because it is architecture
dependent. It allows to connect tracers such as ftrace which detects
scheduling latencies, good/bad scheduler decisions. Tools like LTTng can
export this scheduler information along with instrumentation of the rest
of the kernel activity to perform post-mortem analysis on the scheduler
activity.

About the performance impact of tracepoints (which is comparable to
markers), even without immediate values optimizations, tests done by
Hideo Aoki on ia64 show no regression. His test case was using hackbench
on a kernel where scheduler instrumentation (about 5 events in code
scheduler code) was added. See the "Tracepoints" patch header for
performance result detail.

Changelog :

- Change instrumentation location and parameter to match ftrace
  instrumentation, previously done with kernel markers.

[ mingo@elte.hu: conflict resolutions ]
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: 'Peter Zijlstra' <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:30:52 +02:00
Balbir Singh
31a78f23ba mm owner: fix race between swapoff and exit
There's a race between mm->owner assignment and swapoff, more easily
seen when task slab poisoning is turned on.  The condition occurs when
try_to_unuse() runs in parallel with an exiting task.  A similar race
can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats>
or ptrace or page migration.

CPU0                                    CPU1
                                        try_to_unuse
                                        looks at mm = task0->mm
                                        increments mm->mm_users
task 0 exits
mm->owner needs to be updated, but no
new owner is found (mm_users > 1, but
no other task has task->mm = task0->mm)
mm_update_next_owner() leaves
                                        mmput(mm) decrements mm->mm_users
task0 freed
                                        dereferencing mm->owner fails

The fix is to notify the subsystem via mm_owner_changed callback(),
if no new owner is found, by specifying the new task as NULL.

Jiri Slaby:
mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but
must be set after that, so as not to pass NULL as old owner causing oops.

Daisuke Nishimura:
mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task()
and its callers need to take account of this situation to avoid oops.

Hugh Dickins:
Lockdep warning and hang below exec_mmap() when testing these patches.
exit_mm() up_reads mmap_sem before calling mm_update_next_owner(),
so exec_mmap() now needs to do the same.  And with that repositioning,
there's now no point in mm_need_new_owner() allowing for NULL mm.

Reported-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-29 08:41:47 -07:00
Frank Mayhar
f06febc96b timers: fix itimer/many thread hang
Overview

This patch reworks the handling of POSIX CPU timers, including the
ITIMER_PROF, ITIMER_VIRT timers and rlimit handling.  It was put together
with the help of Roland McGrath, the owner and original writer of this code.

The problem we ran into, and the reason for this rework, has to do with using
a profiling timer in a process with a large number of threads.  It appears
that the performance of the old implementation of run_posix_cpu_timers() was
at least O(n*3) (where "n" is the number of threads in a process) or worse.
Everything is fine with an increasing number of threads until the time taken
for that routine to run becomes the same as or greater than the tick time, at
which point things degrade rather quickly.

This patch fixes bug 9906, "Weird hang with NPTL and SIGPROF."

Code Changes

This rework corrects the implementation of run_posix_cpu_timers() to make it
run in constant time for a particular machine.  (Performance may vary between
one machine and another depending upon whether the kernel is built as single-
or multiprocessor and, in the latter case, depending upon the number of
running processors.)  To do this, at each tick we now update fields in
signal_struct as well as task_struct.  The run_posix_cpu_timers() function
uses those fields to make its decisions.

We define a new structure, "task_cputime," to contain user, system and
scheduler times and use these in appropriate places:

struct task_cputime {
	cputime_t utime;
	cputime_t stime;
	unsigned long long sum_exec_runtime;
};

This is included in the structure "thread_group_cputime," which is a new
substructure of signal_struct and which varies for uniprocessor versus
multiprocessor kernels.  For uniprocessor kernels, it uses "task_cputime" as
a simple substructure, while for multiprocessor kernels it is a pointer:

struct thread_group_cputime {
	struct task_cputime totals;
};

struct thread_group_cputime {
	struct task_cputime *totals;
};

We also add a new task_cputime substructure directly to signal_struct, to
cache the earliest expiration of process-wide timers, and task_cputime also
replaces the it_*_expires fields of task_struct (used for earliest expiration
of thread timers).  The "thread_group_cputime" structure contains process-wide
timers that are updated via account_user_time() and friends.  In the non-SMP
case the structure is a simple aggregator; unfortunately in the SMP case that
simplicity was not achievable due to cache-line contention between CPUs (in
one measured case performance was actually _worse_ on a 16-cpu system than
the same test on a 4-cpu system, due to this contention).  For SMP, the
thread_group_cputime counters are maintained as a per-cpu structure allocated
using alloc_percpu().  The timer functions update only the timer field in
the structure corresponding to the running CPU, obtained using per_cpu_ptr().

We define a set of inline functions in sched.h that we use to maintain the
thread_group_cputime structure and hide the differences between UP and SMP
implementations from the rest of the kernel.  The thread_group_cputime_init()
function initializes the thread_group_cputime structure for the given task.
The thread_group_cputime_alloc() is a no-op for UP; for SMP it calls the
out-of-line function thread_group_cputime_alloc_smp() to allocate and fill
in the per-cpu structures and fields.  The thread_group_cputime_free()
function, also a no-op for UP, in SMP frees the per-cpu structures.  The
thread_group_cputime_clone_thread() function (also a UP no-op) for SMP calls
thread_group_cputime_alloc() if the per-cpu structures haven't yet been
allocated.  The thread_group_cputime() function fills the task_cputime
structure it is passed with the contents of the thread_group_cputime fields;
in UP it's that simple but in SMP it must also safely check that tsk->signal
is non-NULL (if it is it just uses the appropriate fields of task_struct) and,
if so, sums the per-cpu values for each online CPU.  Finally, the three
functions account_group_user_time(), account_group_system_time() and
account_group_exec_runtime() are used by timer functions to update the
respective fields of the thread_group_cputime structure.

Non-SMP operation is trivial and will not be mentioned further.

The per-cpu structure is always allocated when a task creates its first new
thread, via a call to thread_group_cputime_clone_thread() from copy_signal().
It is freed at process exit via a call to thread_group_cputime_free() from
cleanup_signal().

All functions that formerly summed utime/stime/sum_sched_runtime values from
from all threads in the thread group now use thread_group_cputime() to
snapshot the values in the thread_group_cputime structure or the values in
the task structure itself if the per-cpu structure hasn't been allocated.

Finally, the code in kernel/posix-cpu-timers.c has changed quite a bit.
The run_posix_cpu_timers() function has been split into a fast path and a
slow path; the former safely checks whether there are any expired thread
timers and, if not, just returns, while the slow path does the heavy lifting.
With the dedicated thread group fields, timers are no longer "rebalanced" and
the process_timer_rebalance() function and related code has gone away.  All
summing loops are gone and all code that used them now uses the
thread_group_cputime() inline.  When process-wide timers are set, the new
task_cputime structure in signal_struct is used to cache the earliest
expiration; this is checked in the fast path.

Performance

The fix appears not to add significant overhead to existing operations.  It
generally performs the same as the current code except in two cases, one in
which it performs slightly worse (Case 5 below) and one in which it performs
very significantly better (Case 2 below).  Overall it's a wash except in those
two cases.

I've since done somewhat more involved testing on a dual-core Opteron system.

Case 1: With no itimer running, for a test with 100,000 threads, the fixed
	kernel took 1428.5 seconds, 513 seconds more than the unfixed system,
	all of which was spent in the system.  There were twice as many
	voluntary context switches with the fix as without it.

Case 2: With an itimer running at .01 second ticks and 4000 threads (the most
	an unmodified kernel can handle), the fixed kernel ran the test in
	eight percent of the time (5.8 seconds as opposed to 70 seconds) and
	had better tick accuracy (.012 seconds per tick as opposed to .023
	seconds per tick).

Case 3: A 4000-thread test with an initial timer tick of .01 second and an
	interval of 10,000 seconds (i.e. a timer that ticks only once) had
	very nearly the same performance in both cases:  6.3 seconds elapsed
	for the fixed kernel versus 5.5 seconds for the unfixed kernel.

With fewer threads (eight in these tests), the Case 1 test ran in essentially
the same time on both the modified and unmodified kernels (5.2 seconds versus
5.8 seconds).  The Case 2 test ran in about the same time as well, 5.9 seconds
versus 5.4 seconds but again with much better tick accuracy, .013 seconds per
tick versus .025 seconds per tick for the unmodified kernel.

Since the fix affected the rlimit code, I also tested soft and hard CPU limits.

Case 4: With a hard CPU limit of 20 seconds and eight threads (and an itimer
	running), the modified kernel was very slightly favored in that while
	it killed the process in 19.997 seconds of CPU time (5.002 seconds of
	wall time), only .003 seconds of that was system time, the rest was
	user time.  The unmodified kernel killed the process in 20.001 seconds
	of CPU (5.014 seconds of wall time) of which .016 seconds was system
	time.  Really, though, the results were too close to call.  The results
	were essentially the same with no itimer running.

Case 5: With a soft limit of 20 seconds and a hard limit of 2000 seconds
	(where the hard limit would never be reached) and an itimer running,
	the modified kernel exhibited worse tick accuracy than the unmodified
	kernel: .050 seconds/tick versus .028 seconds/tick.  Otherwise,
	performance was almost indistinguishable.  With no itimer running this
	test exhibited virtually identical behavior and times in both cases.

In times past I did some limited performance testing.  those results are below.

On a four-cpu Opteron system without this fix, a sixteen-thread test executed
in 3569.991 seconds, of which user was 3568.435s and system was 1.556s.  On
the same system with the fix, user and elapsed time were about the same, but
system time dropped to 0.007 seconds.  Performance with eight, four and one
thread were comparable.  Interestingly, the timer ticks with the fix seemed
more accurate:  The sixteen-thread test with the fix received 149543 ticks
for 0.024 seconds per tick, while the same test without the fix received 58720
for 0.061 seconds per tick.  Both cases were configured for an interval of
0.01 seconds.  Again, the other tests were comparable.  Each thread in this
test computed the primes up to 25,000,000.

I also did a test with a large number of threads, 100,000 threads, which is
impossible without the fix.  In this case each thread computed the primes only
up to 10,000 (to make the runtime manageable).  System time dominated, at
1546.968 seconds out of a total 2176.906 seconds (giving a user time of
629.938s).  It received 147651 ticks for 0.015 seconds per tick, still quite
accurate.  There is obviously no comparable test without the fix.

Signed-off-by: Frank Mayhar <fmayhar@google.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-14 16:25:35 +02:00
Balbir Singh
49048622ea sched: fix process time monotonicity
Spencer reported a problem where utime and stime were going negative despite
the fixes in commit b27f03d4bd. The suspected
reason for the problem is that signal_struct maintains it's own utime and
stime (of exited tasks), these are not updated using the new task_utime()
routine, hence sig->utime can go backwards and cause the same problem
to occur (sig->utime, adds tsk->utime and not task_utime()). This patch
fixes the problem

TODO: using max(task->prev_utime, derived utime) works for now, but a more
generic solution is to implement cputime_max() and use the cputime_gt()
function for comparison.

Reported-by: spencer@bluehost.com
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-05 18:14:35 +02:00
Oleg Nesterov
950bbabb5a pid_ns: (BUG 11391) change ->child_reaper when init->group_leader exits
We don't change pid_ns->child_reaper when the main thread of the
subnamespace init exits.  As Robert Rex <robert.rex@exasol.com> pointed
out this is wrong.

Yes, the re-parenting itself works correctly, but if the reparented task
exits it needs ->parent->nsproxy->pid_ns in do_notify_parent(), and if the
main thread is zombie its ->nsproxy was already cleared by
exit_task_namespaces().

Introduce the new function, find_new_reaper(), which finds the new
->parent for the re-parenting and changes ->child_reaper if needed.  Kill
the now unneeded exit_child_reaper().

Also move the changing of ->child_reaper from zap_pid_ns_processes() to
find_new_reaper(), this consolidates the games with ->child_reaper and
makes it stable under tasklist_lock.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=11391

Reported-by: Robert Rex <robert.rex@exasol.com>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-02 19:21:38 -07:00
Steve VanDeBogart
2633f0e57b exit signals: use of uninitialized field notify_count
task->signal->notify_count is only initialized if
task->signal->group_exit_task is not NULL.  Reorder a conditional so
that uninitialised memory is not used.  Found by Valgrind.

Signed-off-by: Steve VanDeBogart <vandebo-lkml@nerdbox.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-27 09:10:09 +02:00
Roland McGrath
5c7edcd7ee tracehook: fix exit_signal=0 case
My commit 2b2a1ff64a introduced a regression
(sorry about that) for the odd case of exit_signal=0 (e.g. clone_flags=0).
This is not a normal use, but it's used by a case in the glibc test suite.

Dying with exit_signal=0 sends no signal, but it's supposed to wake up a
parent's blocked wait*() calls (unlike the delayed_group_leader case).
This fixes tracehook_notify_death() and its caller to distinguish a
"signal 0" wakeup from the delayed_group_leader case (with no wakeup).

Signed-off-by: Roland McGrath <roland@redhat.com>
Tested-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-01 12:01:11 -07:00
Andrea Righi
5995477ab7 task IO accounting: improve code readability
Put all i/o statistics in struct proc_io_accounting and use inline functions to
initialize and increment statistics, removing a lot of single variable
assignments.

This also reduces the kernel size as following (with CONFIG_TASK_XACCT=y and
CONFIG_TASK_IO_ACCOUNTING=y).

    text    data     bss     dec     hex filename
   11651       0       0   11651    2d83 kernel/exit.o.before
   11619       0       0   11619    2d63 kernel/exit.o.after
   10886     132     136   11154    2b92 kernel/fork.o.before
   10758     132     136   11026    2b12 kernel/fork.o.after

 3082029  807968 4818600 8708597  84e1f5 vmlinux.o.before
 3081869  807968 4818600 8708437  84e155 vmlinux.o.after

Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-27 09:58:20 -07:00
Al Viro
7f2da1e7d0 [PATCH] kill altroot
long overdue...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-26 20:53:20 -04:00
Roland McGrath
2b2a1ff64a tracehook: death
This moves the ptrace logic in task death (exit_notify) into tracehook.h
inlines.  Some code is rearranged slightly to make things nicer.  There is
no change, only cleanup.

There is one hook called with the tasklist_lock write-locked, as ptrace
needs.  There is also a new hook called after exit_state changes and
without locks.  This is a better place for tracing work to be in the
future, since it doesn't delay the whole system with locking.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:09 -07:00
Roland McGrath
dae33574dc tracehook: release_task
This moves the ptrace-related logic from release_task into tracehook.h and
ptrace.h inlines.  It provides clean hooks both before and after locking
tasklist_lock, for future tracing logic to do more cleanup without the
lock.

This also changes release_task() itself in the rare "zap_leader" case to
set the leader to EXIT_DEAD before iterating.  This maintains the
invariant that release_task() only ever handles a task in EXIT_DEAD.  This
is a common-sense invariant that is already always true except in this one
arcane case of zombie leader whose parent ignores SIGCHLD.

This change is harmless and only costs one store in this one rare case.
It keeps the expected state more consisently sane, which is nicer when
debugging weirdness in release_task().  It also lets some future code in
the tracehook entry points rely on this invariant for bookkeeping.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:08 -07:00
Roland McGrath
30199f5a46 tracehook: exit
This moves the PTRACE_EVENT_EXIT tracing into a tracehook.h inline,
tracehook_report_exec().  The change has no effect, just clean-up.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:08 -07:00
Andrea Righi
297c5d9263 task IO accounting: provide distinct tgid/tid I/O statistics
Report per-thread I/O statistics in /proc/pid/task/tid/io and aggregate
parent I/O statistics in /proc/pid/io.  This approach follows the same
model used to account per-process and per-thread CPU times.

As a practial application, this allows for example to quickly find the top
I/O consumer when a process spawns many child threads that perform the
actual I/O work, because the aggregated I/O statistics can always be found
in /proc/pid/io.

[ Oleg Nesterov points out that we should check that the task is still
  alive before we iterate over the threads, but also says that we can do
  that fixup on top of this later.  - Linus ]

Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Cc: Matt Heaton <matt@hostmonster.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Acked-by-with-comments: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:47 -07:00
Oleg Nesterov
a94e2d408e coredump: kill mm->core_done
Now that we have core_state->dumper list we can use it to wake up the
sub-threads waiting for the coredump completion.

This uglifies the code and .text grows by 47 bytes, but otoh mm_struct
lessens by sizeof(struct completion).  Also, with this change we can
decouple exit_mm() from the coredumping code.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:40 -07:00
Oleg Nesterov
b564daf806 coredump: construct the list of coredumping threads at startup time
binfmt->core_dump() has to iterate over the all threads in system in order
to find the coredumping threads and construct the list using the
GFP_ATOMIC allocations.

With this patch each thread allocates the list node on exit_mm()'s stack and
adds itself to the list.

This allows us to do further changes:

	- simplify ->core_dump()

	- change exit_mm() to clear ->mm first, then wait for ->core_done.
	  this makes the coredumping process visible to oom_kill

	- kill mm->core_done

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:40 -07:00
Oleg Nesterov
c5f1cc8c18 coredump: turn core_state->nr_threads into atomic_t
Turn core_state->nr_threads into atomic_t and kill now unneeded
down_write(&mm->mmap_sem) in exit_mm().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:39 -07:00
Oleg Nesterov
999d9fc167 coredump: move mm->core_waiters into struct core_state
Move mm->core_waiters into "struct core_state" allocated on stack.  This
shrinks mm_struct a little bit and allows further changes.

This patch mostly does s/core_waiters/core_state.  The only essential
change is that coredump_wait() must clear mm->core_state before return.

The coredump_wait()'s path is uglified and .text grows by 30 bytes, this
is fixed by the next patch.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:39 -07:00
Oleg Nesterov
32ecb1f26d coredump: turn mm->core_startup_done into the pointer to struct core_state
mm->core_startup_done points to "struct completion startup_done" allocated
on the coredump_wait()'s stack.  Introduce the new structure, core_state,
which holds this "struct completion".  This way we can add more info
visible to the threads participating in coredump without enlarging
mm_struct.

No changes in affected .o files.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:39 -07:00
Oleg Nesterov
7b34e4283c introduce PF_KTHREAD flag
Introduce the new PF_KTHREAD flag to mark the kernel threads.  It is set
by INIT_TASK() and copied to the forked childs (we could set it in
kthreadd() along with PF_NOFREEZE instead).

daemonize() was changed as well.  In that case testing of PF_KTHREAD is
racy, but daemonize() is hopeless anyway.

This flag is cleared in do_execve(), before search_binary_handler().
Probably not the best place, we can do this in exec_mmap() or in
start_thread(), or clear it along with PF_FORKNOEXEC.  But I think this
doesn't matter in practice, and if do_execve() fails kthread should die
soon.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:39 -07:00
Oleg Nesterov
3854a77182 __exit_signal: don't take rcu lock
There is no reason for rcu_read_lock() in __exit_signal().  tsk->sighand
can only be changed if tsk does exec, obviously this is not possible.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:38 -07:00
Roland McGrath
666f164f4f fix dangling zombie when new parent ignores children
This fixes an arcane bug that we think was a regression introduced
by commit b2b2cbc4b2.  When a parent
ignores SIGCHLD (or uses SA_NOCLDWAIT), its children would self-reap
but they don't if it's using ptrace on them.  When the parent thread
later exits and ceases to ptrace a child but leaves other live
threads in the parent's thread group, any zombie children are left
dangling.  The fix makes them self-reap then, as they would have
done earlier if ptrace had not been in use.

Signed-off-by: Roland McGrath <roland@redhat.com>
2008-07-16 18:02:34 -07:00
Roland McGrath
14dd0b8141 do_wait: return security_task_wait() error code in place of -ECHILD
This reverts the effect of commit f2cc3eb133
"do_wait: fix security checks".  That change reverted the effect of commit
7324328446.  The rationale for the original
commit still stands.  The inconsistent treatment of children hidden by
ptrace was an unintended omission in the original change and in no way
invalidates its purpose.

This makes do_wait return the error returned by security_task_wait()
(usually -EACCES) in place of -ECHILD when there are some children the
caller would be able to wait for if not for the permission failure.  A
permission error will give the user a clue to look for security policy
problems, rather than for mysterious wait bugs.

Signed-off-by: Roland McGrath <roland@redhat.com>
2008-07-16 18:02:34 -07:00
Roland McGrath
f470021adb ptrace children revamp
ptrace no longer fiddles with the children/sibling links, and the
old ptrace_children list is gone.  Now ptrace, whether of one's own
children or another's via PTRACE_ATTACH, just uses the new ptraced
list instead.

There should be no user-visible difference that matters.  The only
change is the order in which do_wait() sees multiple stopped
children and stopped ptrace attachees.  Since wait_task_stopped()
was changed earlier so it no longer reorders the children list, we
already know this won't cause any new problems.

Signed-off-by: Roland McGrath <roland@redhat.com>
2008-07-16 18:02:33 -07:00
Roland McGrath
98abed0200 do_wait reorganization
This breaks out the guts of do_wait into three subfunctions.
The control flow is less nonobvious without so much goto.
do_wait_thread and ptrace_do_wait contain the main work of the outer loop.
wait_consider_task contains the main work of the inner loop.

Signed-off-by: Roland McGrath <roland@redhat.com>
2008-07-16 18:02:33 -07:00
Jens Axboe
da9cbc8739 block: blkdev.h cleanup, move iocontext stuff to iocontext.h
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03 13:21:14 +02:00
Eric Sandeen
7c9f8861e6 stackprotector: use canary at end of stack to indicate overruns at oops time
(Updated with a common max-stack-used checker that knows about
the canary, as suggested by Joe Perches)

Use a canary at the end of the stack to clearly indicate
at oops time whether the stack has ever overflowed.

This is a very simple implementation with a couple of
drawbacks:

1) a thread may legitimately use exactly up to the last
   word on the stack

 -- but the chances of doing this and then oopsing later seem slim

2) it's possible that the stack usage isn't dense enough
   that the canary location could get skipped over

 -- but the worst that happens is that we don't flag the overrun
 -- though this happens fairly often in my testing :(

With the code in place, an intentionally-bloated stack oops might
do:

BUG: unable to handle kernel paging request at ffff8103f84cc680
IP: [<ffffffff810253df>] update_curr+0x9a/0xa8
PGD 8063 PUD 0
Thread overran stack or stack corrupted
Oops: 0000 [1] SMP
CPU 0
...

... unless the stack overrun is so bad that it corrupts some other
thread.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-26 16:15:33 +02:00
Oleg Nesterov
da7978b034 signals: fix sigqueue_free() vs __exit_signal() race
__exit_signal() does flush_sigqueue(tsk->pending) outside of ->siglock.
This can race with another thread doing sigqueue_free(), we can free the
same SIGQUEUE_PREALLOC sigqueue twice or corrupt the pending->list.

Note that even sys_exit_group() can trigger this race, not only
sys_timer_delete().

Move the callsite of flush_sigqueue(tsk->pending) under ->siglock.

This patch doesn't touch flush_sigqueue(->shared_pending) below, it is
called when there are no other threads which can play with signals, and
sigqueue_free() can't be used outside of our thread group.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-24 09:56:10 -07:00
Al Viro
9f3acc3140 [PATCH] split linux/file.h
Initial splitoff of the low-level stuff; taken to fdtable.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-01 13:08:16 -04:00
Oleg Nesterov
7d8da0962e pids: __set_special_pids: use change_pid() helper
Use change_pid() instead of detach_pid() + attach_pid() in
__set_special_pids().

This way task_session() is not NULL in between.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc:  "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:49 -07:00
Oleg Nesterov
53b6f9fbd3 ptrace: introduce ptrace_reparented() helper
Add another trivial helper for the sake of grep.  It also auto-documents the
fact that ->parent != real_parent implies ->ptrace.

No functional changes.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:38 -07:00
Oleg Nesterov
2800d8d19e document de_thread() with exit_notify() connection
Add a couple of small comments, it is not easy to see what this code does.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:38 -07:00
Oleg Nesterov
376e1d2531 reparent_thread: use same_thread_group()
Trivial, use same_thread_group() in reparent_thread().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:38 -07:00
Oleg Nesterov
d839fd4d2e ptrace: introduce task_detached() helper
exit.c has numerous "->exit_signal == -1" comparisons, this check is subtle
and deserves a helper.  Imho makes the code more parseable for humans.  At
least it's surely more greppable.

Also, a couple of whitespace cleanups. No functional changes.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:38 -07:00
Oleg Nesterov
bfc4b0890a signals: do_group_exit(): use signal_group_exit() more consistently
do_group_exit() checks SIGNAL_GROUP_EXIT to avoid taking sighand->siglock.
Since ed5d2cac11 exec() doesn't set this
flag, we should use signal_group_exit().

This is not needed for correctness, but can speedup the multithreaded exec
and makes the code more consistent.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:33 -07:00
Balbir Singh
cf475ad28a cgroups: add an owner to the mm_struct
Remove the mem_cgroup member from mm_struct and instead adds an owner.

This approach was suggested by Paul Menage.  The advantage of this approach
is that, once the mm->owner is known, using the subsystem id, the cgroup
can be determined.  It also allows several control groups that are
virtually grouped by mm_struct, to exist independent of the memory
controller i.e., without adding mem_cgroup's for each controller, to
mm_struct.

A new config option CONFIG_MM_OWNER is added and the memory resource
controller selects this config option.

This patch also adds cgroup callbacks to notify subsystems when mm->owner
changes.  The mm_cgroup_changed callback is called with the task_lock() of
the new task held and is called just prior to changing the mm->owner.

I am indebted to Paul Menage for the several reviews of this patchset and
helping me make it lighter and simpler.

This patch was tested on a powerpc box, it was compiled with both the
MM_OWNER config turned on and off.

After the thread group leader exits, it's moved to init_css_state by
cgroup_exit(), thus all future charges from runnings threads would be
redirected to the init_css_set's subsystem.

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>,
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:10 -07:00
Lee Schermerhorn
f0be3d32b0 mempolicy: rename mpol_free to mpol_put
This is a change that was requested some time ago by Mel Gorman.  Makes sense
to me, so here it is.

Note: I retain the name "mpol_free_shared_policy()" because it actually does
free the shared_policy, which is NOT a reference counted object.  However, ...

The mempolicy object[s] referenced by the shared_policy are reference counted,
so mpol_put() is used to release the reference held by the shared_policy.  The
mempolicy might not be freed at this time, because some task attached to the
shared object associated with the shared policy may be in the process of
allocating a page based on the mempolicy.  In that case, the task performing
the allocation will hold a reference on the mempolicy, obtained via
mpol_shared_policy_lookup().  The mempolicy will be freed when all tasks
holding such a reference have called mpol_put() for the mempolicy.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:23 -07:00
Al Viro
3b1253880b [PATCH] sanitize unshare_files/reset_files_struct
* let unshare_files() give caller the displaced files_struct
* don't bother with grabbing reference only to drop it in the
  caller if it hadn't been shared in the first place
* in that form unshare_files() is trivially implemented via
  unshare_fd(), so we eliminate the duplicate logics in fork.c
* reset_files_struct() is not just only called for current;
  it will break the system if somebody ever calls it for anything
  else (we can't modify ->files of somebody else).  Lose the
  task_struct * argument.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-25 09:23:59 -04:00
Al Viro
fd8328be87 [PATCH] sanitize handling of shared descriptor tables in failing execve()
* unshare_files() can fail; doing it after irreversible actions is wrong
  and de_thread() is certainly irreversible.
* since we do it unconditionally anyway, we might as well do it in do_execve()
  and save ourselves the PITA in binfmt handlers, etc.
* while we are at it, binfmt_som actually leaked files_struct on failure.

As a side benefit, unshare_files(), put_files_struct() and reset_files_struct()
become unexported.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-25 09:23:53 -04:00
Al Viro
1ec7f1ddbe [PATCH] get rid of __exit_files(), __exit_fs() and __put_fs_struct()
The only reason to have separated __...() for those was to keep them inlined
for local users in exit.c.  Since Alexey removed the inline on those, there's
no reason whatsoever to keep them around; just collapse with normal variants.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-22 19:55:09 -04:00
Roland McGrath
54a0151041 asmlinkage_protect replaces prevent_tail_call
The prevent_tail_call() macro works around the problem of the compiler
clobbering argument words on the stack, which for asmlinkage functions
is the caller's (user's) struct pt_regs.  The tail/sibling-call
optimization is not the only way that the compiler can decide to use
stack argument words as scratch space, which we have to prevent.
Other optimizations can do it too.

Until we have new compiler support to make "asmlinkage" binding on the
compiler's own use of the stack argument frame, we have work around all
the manifestations of this issue that crop up.

More cases seem to be prevented by also keeping the incoming argument
variables live at the end of the function.  This makes their original
stack slots attractive places to leave those variables, so the compiler
tends not clobber them for something else.  It's still no guarantee, but
it handles some observed cases that prevent_tail_call() did not.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-10 17:28:26 -07:00
Roland McGrath
6efcae4601 Fix waitid si_code regression
In commit ee7c82da83 ("wait_task_stopped:
simplify and fix races with SIGCONT/SIGKILL/untrace"), the magic (short)
cast when storing si_code was lost in wait_task_stopped.  This leaks the
in-kernel CLD_* values that do not match what userland expects.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-08 11:54:00 -08:00
Oleg Nesterov
821c7de719 exit_notify: fix kill_orphaned_pgrp() usage with mt exit
1. exit_notify() always calls kill_orphaned_pgrp(). This is wrong, we
   should do this only when the whole process exits.

2. exit_notify() uses "current" as "ignored_task", obviously wrong.
   Use ->group_leader instead.

Test case:

	void hup(int sig)
	{
		printf("HUP received\n");
	}

	void *tfunc(void *arg)
	{
		sleep(2);
		printf("sub-thread exited\n");
		return NULL;
	}

	int main(int argc, char *argv[])
	{
		if (!fork()) {
			signal(SIGHUP, hup);
			kill(getpid(), SIGSTOP);
			exit(0);
		}

		pthread_t thr;
		pthread_create(&thr, NULL, tfunc, NULL);

		sleep(1);
		printf("main thread exited\n");
		syscall(__NR_exit, 0);

		return 0;
	}

output:

	main thread exited
	HUP received
	Hangup

With this patch the output is:

	main thread exited
	sub-thread exited
	HUP received

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-03 14:53:16 -08:00
Oleg Nesterov
05e83df624 will_become_orphaned_pgrp: partially fix insufficient ->exit_state check
p->exit_state != 0 doesn't mean this process is dead, it may have
sub-threads.  Change the code to use "p->exit_state && thread_group_empty(p)"
instead.

Without this patch, ^Z doesn't deliver SIGTSTP to the foreground process
if the main thread has exited.

However, the new check is not perfect either.  There is a window when
exit_notify() drops tasklist and before release_task().  Suppose that
the last (non-leader) thread exits.  This means that entire group exits,
but thread_group_empty() is not true yet.

As Eric pointed out, is_global_init() is wrong as well, but I did not
dare to do other changes.

Just for the record, has_stopped_jobs() is absolutely wrong too.  But we
can't fix it now, we should first fix SIGNAL_STOP_STOPPED issues.

Even with this patch ^Z doesn't play well with the dead main thread.
The task is stopped correctly but do_wait(WSTOPPED) won't see it.  This
is another unrelated issue, will be (hopefully) fixed separately.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-03 14:53:16 -08:00
Oleg Nesterov
f49ee505b1 introduce kill_orphaned_pgrp() helper
Factor out the common code in reparent_thread() and exit_notify().

No functional changes.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-03 14:53:16 -08:00
Jan Blunck
6ac08c39a1 Use struct path in fs_struct
* Use struct path in fs_struct.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-14 21:13:33 -08:00
Harvey Harrison
7ad5b3a505 kernel: remove fastcall in kernel/*
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:31 -08:00
Pavel Emelyanov
6c5f3e7b43 Pidns: make full use of xxx_vnr() calls
Some time ago the xxx_vnr() calls (e.g.  pid_vnr or find_task_by_vpid) were
_all_ converted to operate on the current pid namespace.  After this each call
like xxx_nr_ns(foo, current->nsproxy->pid_ns) is nothing but a xxx_vnr(foo)
one.

Switch all the xxx_nr_ns() callers to use the xxx_vnr() calls where
appropriate.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Reviewed-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:29 -08:00
Eric W. Biederman
161550d74c pid: sys_wait... fixes
This modifies do_wait and eligible child to take a pair of enum pid_type
and struct pid *pid to precisely specify what set of processes are eligible
to be waited for, instead of the raw pid_t value from sys_wait4.

This fixes a bug in sys_waitid where you could not wait for children in
just process group 1.

This fixes a pid namespace crossing case in eligible_child.  Allowing us to
wait for a processes in our current process group even if our current
process group == 0.

This allows the no child with this pid case to be optimized.  This allows
us to optimize the pid membership test in eligible child to be optimized.

This even closes a theoretical pid wraparound race where in a threaded
parent if two threads are waiting for the same child and one thread picks
up the child and the pid numbers wrap around and generate another child
with that same pid before the other thread is scheduled (teribly insanely
unlikely) we could end up waiting on the second child with the same pid#
and not discover that the specific child we were waiting for has exited.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:27 -08:00
Oleg Nesterov
5dee1707df move the related code from exit_notify() to exit_signals()
The previous bugfix was not optimal, we shouldn't care about group stop
when we are the only thread or the group stop is in progress.  In that case
nothing special is needed, just set PF_EXITING and return.

Also, take the related "TIF_SIGPENDING re-targeting" code from exit_notify().

So, from the performance POV the only difference is that we don't trust
!signal_pending() until we take ->siglock.  But this in fact fixes another
___pure___ theoretical minor race.  __group_complete_signal() finds the
task without PF_EXITING and chooses it as the target for signal_wake_up().
But nothing prevents this task from exiting in between without noticing the
pending signal and thus unpredictably delaying the actual delivery.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:27 -08:00
Oleg Nesterov
d12619b5ff fix group stop with exit race
do_signal_stop() counts all sub-thread and sets ->group_stop_count
accordingly.  Every thread should decrement ->group_stop_count and stop,
the last one should notify the parent.

However a sub-thread can exit before it notices the signal_pending(), or it
may be somewhere in do_exit() already.  In that case the group stop never
finishes properly.

Note: this is a minimal fix, we can add some optimizations later.  Say we
can return quickly if thread_group_empty().  Also, we can move some signal
related code from exit_notify() to exit_signals().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:27 -08:00
Oleg Nesterov
297bd42b15 move daemonized kernel threads into the swapper's session
Daemonized kernel threads run in the init's session. This doesn't match the
behaviour of kthread_create()'ed threads, and this is one of the 2 reasons
why we need a special hack in sys_setsid().

Now that set_special_pids() was changed to use struct pid, not pid_t, we can
use init_struct_pid and set 0,0 special pids.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:27 -08:00
Oleg Nesterov
8520d7c7f8 teach set_special_pids() to use struct pid
Change set_special_pids() to work with struct pid, not pid_t from global name
space. This again speedups and imho cleanups the code, also a preparation for
the next patch.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:27 -08:00
Oleg Nesterov
c543f1ee08 wait_task_zombie: remove ->exit_state/exit_signal checks for WNOWAIT
The first "p->exit_state != EXIT_ZOMBIE" check doesn't make too much sense.
The exit_state was EXIT_ZOMBIE when the function was called, and another
thread can change it to EXIT_DEAD right after the check.

The second condition is not possible, detached non-traced threads were already
filtered out by eligible_child(), we didn't drop tasklist since then.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:27 -08:00
Oleg Nesterov
3a515e4a62 wait_task_continued/zombie: don't use task_pid_nr_ns() lockless
Surprise, the other two wait_task_*() functions also abuse the
task_pid_nr_ns() function, and may cause read-after-free or report nr == 0
in wait_task_continued().  wait_task_zombie() doesn't have this problem,
but it is still better to cache pid_t rather than call task_pid_nr_ns()
three times on the saved pid_namespace.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:26 -08:00
Oleg Nesterov
f2cc3eb133 do_wait: fix security checks
Imho, the current usage of security_task_wait() is not logical.

Suppose we have the single child p, and security_task_wait(p) return
-EANY.  In that case waitpid(-1) returns this error.  Why? Isn't it
better to return ECHLD? We don't really have reapable children.

Now suppose that child was stolen by gdb.  In that case we find this
child on ->ptrace_children and set flag = 1, but we don't check that the
child was denied.  So, do_wait(..., WNOHANG) returns 0, this doesn't
match the behaviour above.  Without WNOHANG do_wait() blocks only to
return the error later, when the child will be untraced.  Inho, really
strange.

I think eligible_child() should return the error only if the child's pid
was requested explicitly, otherwise we should silently ignore the tasks
which were nacked by security_task_wait().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:26 -08:00
Oleg Nesterov
96fabbf55a do_wait: cleanup delay_group_leader() usage
eligible_child() == 2 means delay_group_leader().  With the previous patch
this only matters for EXIT_ZOMBIE task, we can move that special check to
the only place it is really needed.

Also, with this patch we don't skip security_task_wait() for the group
leaders in a non-empty thread group.  I don't really understand the exact
semantics of security_task_wait(), but imho this change is a bugfix.

Also rearrange the code a bit to kill an ugly "check_continued" backdoor.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:26 -08:00
Oleg Nesterov
1bad95c3be wait_task_stopped(): remove unneeded delay_group_leader check
wait_task_stopped() doesn't need the "delay_group_leader" parameter.  If
the child is not traced it must be a group leader.  With or without
subthreads ->group_stop_count == 0 when the whole task is stopped.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Mika Penttila <mika.penttila@kolumbus.fi>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:26 -08:00
Oleg Nesterov
9cbab81005 do_wait: factor out "retval != 0" checks
Every branch if the main "if" statement does the same code at the end.  Move
it down.  Also, fix the indentation.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:26 -08:00
Oleg Nesterov
ee7c82da83 wait_task_stopped: simplify and fix races with SIGCONT/SIGKILL/untrace
wait_task_stopped() has multiple races with SIGCONT/SIGKILL.  tasklist_lock
does not pin the child in TASK_TRACED/TASK_STOPPED stated, almost all info
reported (including exit_code) may be wrong.

In fact, the code under write_lock_irq(tasklist_lock) is not safe.  The child
may be PTRACE_DETACH'ed at this time by another subthread, in that case it is
possible we are no longer its ->parent.

Change wait_task_stopped() to take ->siglock before inspecting the task.  This
guarantees that the child can't resume and (for example) clear its
->exit_code, so we don't need to use xchg(&p->exit_code) and re-check.  The
only exception is ptrace_stop() which changes ->state and ->exit_code without
->siglock held during abort.  But this can only happen if both the tracer and
the tracee are dying (coredump is in progress), we don't care.

With this patch wait_task_stopped() doesn't move the child to the end of
the ->parent list on success.  This optimization could be restored, but
in that case we have to take write_lock(tasklist) and do some nasty
checks.

Also change the do_wait() since we don't return EAGAIN any longer.

[akpm@linux-foundation.org: fix up after Willy renamed everything]
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:26 -08:00
Oleg Nesterov
34a1738f7d kill my_ptrace_child()
Now that my_ptrace_child() is trivial we can use the "p->ptrace & PT_PTRACED"
inline and simplify the corresponding logic in do_wait: we can't find the
child in TASK_TRACED state without PT_PTRACED flag set, ptrace_untrace()
either sets TASK_STOPPED or wakes up the tracee.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:26 -08:00
Oleg Nesterov
6b39c7bfbd kill PT_ATTACHED
Since the patch

	"Fix ptrace_attach()/ptrace_traceme()/de_thread() race"
	commit f5b40e363a

we set PT_ATTACHED and change child->parent "atomically" wrt task_list lock.

This means we can remove the checks like "PT_ATTACHED && ->parent != ptracer"
which were needed to catch the "ptrace attach is in progress" case.  We can
also remove the flag itself since nobody else uses it.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:26 -08:00
Oleg Nesterov
0a76fe8e50 do_wait: remove one "else if" branch
Minor cleanup. We can remove one "else if" branch.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06 10:41:04 -08:00
Oleg Nesterov
ed5d2cac11 exec: rework the group exit and fix the race with kill
As Roland pointed out, we have the very old problem with exec.  de_thread()
sets SIGNAL_GROUP_EXIT, kills other threads, changes ->group_leader and then
clears signal->flags.  All signals (even fatal ones) sent in this window
(which is not too small) will be lost.

With this patch exec doesn't abuse SIGNAL_GROUP_EXIT.  signal_group_exit(),
the new helper, should be used to detect exit_group() or exec() in progress.
It can have more users, but this patch does only strictly necessary changes.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Robin Holt <holt@sgi.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 09:44:07 -08:00
Pierre Peiffer
06c93e8757 Remove one useless extern declaration
The file exit.c contains one useless extern declaration of sem_exit().
Moreover, it refers to nothing.

This trivial patch removes it.

Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
2008-02-03 16:22:12 +02:00
Matthew Wilcox
338077e54e exit: Use task_is_*
Also restructure the loop in do_wait()

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
2007-12-06 17:35:17 -05:00
Scott James Remnant
e6ceb32aa2 wait_task_stopped(): pass correct exit_code to wait_noreap_copyout()
In wait_task_stopped() exit_code already contains the right value for the
si_status member of siginfo, and this is simply set in the non WNOWAIT
case.

If you call waitid() with a stopped or traced process, you'll get the signal
in siginfo.si_status as expected -- however if you call waitid(WNOWAIT) at the
same time, you'll get the signal << 8 | 0x7f

Pass it unchanged to wait_noreap_copyout(); we would only need to shift it
and add 0x7f if we were returning it in the user status field and that
isn't used for any function that permits WNOWAIT.

Signed-off-by: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-29 09:24:55 -08:00
Oleg Nesterov
c895078355 wait_task_stopped(): don't use task_pid_nr_ns() lockless
wait_task_stopped(WNOWAIT) does task_pid_nr_ns() without tasklist/rcu lock,
we can read an already freed memory.  Use the cached pid_t value.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Looks-good-to: Roland McGrath <roland@redhat.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-29 09:24:52 -08:00
Roland McGrath
a3474224e6 wait_task_stopped: Check p->exit_state instead of TASK_TRACED
The original meaning of the old test (p->state > TASK_STOPPED) was
"not dead", since it was before TASK_TRACED existed and before the
state/exit_state split.  It was a wrong correction in commit
14bf01bb05 to make this test for
TASK_TRACED instead.  It should have been changed when TASK_TRACED
was introducted and again when exit_state was introduced.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Kees Cook <kees@ubuntu.com>
Acked-by: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-15 08:36:27 -08:00
Alexey Dobriyan
a39bc51691 Uninline fork.c/exit.c
Save ~650 bytes here.

add/remove: 4/0 grow/shrink: 0/7 up/down: 430/-1088 (-658)
function                                     old     new   delta
__copy_fs_struct                               -     202    +202
__put_fs_struct                                -     112    +112
__exit_fs                                      -      58     +58
__exit_files                                   -      58     +58
exit_files                                    58       2     -56
put_fs_struct                                112       5    -107
exit_fs                                      161       2    -159
sys_unshare                                  774     590    -184
copy_process                                4031    3840    -191
do_exit                                     1791    1597    -194
copy_fs_struct                               202       5    -197

No difference in lmbench lat_proc tests on 2-way Opteron 246.
Smaaaal degradation on UP P4 (within errors).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:56 -07:00
Pavel Emelyanov
ba25f9dcc4 Use helpers to obtain task pid in printks
The task_struct->pid member is going to be deprecated, so start
using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in
the kernel.

The first thing to start with is the pid, printed to dmesg - in
this case we may safely use task_pid_nr(). Besides, printks produce
more (much more) than a half of all the explicit pid usage.

[akpm@linux-foundation.org: git-drm went and changed lots of stuff]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:43 -07:00
Pavel Emelyanov
9a2e70572e Isolate the explicit usage of signal->pgrp
The pgrp field is not used widely around the kernel so it is now marked as
deprecated with appropriate comment.

The initialization of INIT_SIGNALS is trimmed because
a) they are set to 0 automatically;
b) gcc cannot properly initialize two anonymous (the second one
   is the one with the session) unions. In this particular case
   to make it compile we'd have to add some field initialized
   right before the .pgrp.

This is the same patch as the 1ec320afdc one
(from Cedric), but for the pgrp field.

Some progress report:

We have to deprecate the pid, tgid, session and pgrp fields on struct
task_struct and struct signal_struct.  The session and pgrp are already
deprecated.  The tgid value is close to being such - the worst known usage
in in fs/locks.c and audit code.  The pid field deprecation is mainly
blocked by numerous printk-s around the kernel that print the tsk->pid to
log.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:43 -07:00
Pavel Emelyanov
b488893a39 pid namespaces: changes to show virtual ids to user
This is the largest patch in the set. Make all (I hope) the places where
the pid is shown to or get from user operate on the virtual pids.

The idea is:
 - all in-kernel data structures must store either struct pid itself
   or the pid's global nr, obtained with pid_nr() call;
 - when seeking the task from kernel code with the stored id one
   should use find_task_by_pid() call that works with global pids;
 - when showing pid's numerical value to the user the virtual one
   should be used, but however when one shows task's pid outside this
   task's namespace the global one is to be used;
 - when getting the pid from userspace one need to consider this as
   the virtual one and use appropriate task/pid-searching functions.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: nuther build fix]
[akpm@linux-foundation.org: yet nuther build fix]
[akpm@linux-foundation.org: remove unneeded casts]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:40 -07:00
Sukadev Bhattiprolu
3eb07c8c8a pid namespaces: destroy pid namespace on init's death
Terminate all processes in a namespace when the reaper of the namespace is
exiting.  We do this by walking the pidmap of the namespace and sending
SIGKILL to all processes.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:40 -07:00
Pavel Emelyanov
60347f6716 pid namespaces: prepare proc_flust_task() to flush entries from multiple proc trees
The first part is trivial - we just make the proc_flush_task() to operate on
arbitrary vfsmount with arbitrary ids and pass the pid and global proc_mnt to
it.

The other change is more tricky: I moved the proc_flush_task() call in
release_task() higher to address the following problem.

When flushing task from many proc trees we need to know the set of ids (not
just one pid) to find the dentries' names to flush.  Thus we need to pass the
task's pid to proc_flush_task() as struct pid is the only object that can
provide all the pid numbers.  But after __exit_signal() task has detached all
his pids and this information is lost.

This creates a tiny gap for proc_pid_lookup() to bring some dentries back to
tree and keep them in hash (since pids are still alive before __exit_signal())
till the next shrink, but since proc_flush_task() does not provide a 100%
guarantee that the dentries will be flushed, this is OK to do so.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:38 -07:00
Pavel Emelyanov
2e4a707269 pid namespaces: move exit_task_namespaces()
Make task release its namespaces after it has reparented all his children to
child_reaper, but before it notifies its parent about its death.

The reason to release namespaces after reparenting is that when task exits it
may send a signal to its parent (SIGCHLD), but if the parent has already
exited its namespaces there will be no way to decide what pid to dever to him
- parent can be from different namespace.

The reason to release namespace before notifying the parent it that when task
sends a SIGCHLD to parent it can call wait() on this taks and release it.  But
releasing the mnt namespace implies dropping of all the mounts in the mnt
namespace and NFS expects the task to have valid sighand pointer.

Thanks to Oleg for pointing out some races that can apear and helping with
patches and fixes.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:38 -07:00
Oleg Nesterov
762a24beed pid namespaces: rework forget_original_parent()
A pid namespace is a "view" of a particular set of tasks on the system.  They
work in a similar way to filesystem namespaces.  A file (or a process) can be
accessed in multiple namespaces, but it may have a different name in each.  In
a filesystem, this name might be /etc/passwd in one namespace, but
/chroot/etc/passwd in another.

For processes, a process may have pid 1234 in one namespace, but be pid 1 in
another.  This allows new pid namespaces to have basically arbitrary pids, and
not have to worry about what pids exist in other namespaces.  This is
essential for checkpoint/restart where a restarted process's pid might collide
with an existing process on the system's pid.

In this particular implementation, pid namespaces have a parent-child
relationship, just like processes.  A process in a pid namespace may see all
of the processes in the same namespace, as well as all of the processes in all
of the namespaces which are children of its namespace.  Processes may not,
however, see others which are in their parent's namespace, but not in their
own.  The same goes for sibling namespaces.

The know issue to be solved in the nearest future is signal handling in the
namespace boundary.  That is, currently the namespace's init is treated like
an ordinary task that can be killed from within an namespace.  Ideally, the
signal handling by the namespace's init should have two sides: when signaling
the init from its namespace, the init should look like a real init task, i.e.
receive only those signals, that is explicitly wants to; when signaling the
init from one of the parent namespaces, init should look like an ordinary
task, i.e.  receive any signal, only taking the general permissions into
account.

The pid namespace was developed by Pavel Emlyanov and Sukadev Bhattiprolu and
we eventually came to almost the same implementation, which differed in some
details.  This set is based on Pavel's patches, but it includes comments and
patches that from Sukadev.

Many thanks to Oleg, who reviewed the patches, pointed out many BUGs and made
valuable advises on how to make this set cleaner.

This patch:

We have to call exit_task_namespaces() only after the exiting task has
reparented all his children and is sure that no other threads will reparent
theirs for it.  Why this is needed is explained in appropriate patch.  This
one only reworks the forget_original_parent() so that after calling this a
task cannot be/become parent of any other task.

We check PF_EXITING instead of ->exit_state while choosing the new parent.
Note that tasklits_lock acts as a barrier, everyone who takes tasklist after
us (when forget_original_parent() drops it) must see PF_EXITING.

The other changes are just cleanups.  They just move some code from
exit_notify to forget_original_parent().  It is a bit silly to declare
ptrace_dead in exit_notify(), take tasklist, pass ptrace_dead to
forget_original_parent(), unlock-lock-unlock tasklist, and then use
ptrace_dead.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:38 -07:00
Daniel Walker
d4c5e41f3f whitespace fixes: task exit handling
Signed-off-by: Daniel Walker <dwalker@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:38 -07:00
Matthias Kaehlcke
03ff17979c kernel/exit.c: Use list_for_each_entry(_safe) instead of list_for_each(_safe)
kernel/exit.c: Convert list_for_each(_safe) to
list_for_each_entry(_safe) in forget_original_parent(), exit_notify()
and do_wait()

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:38 -07:00
Pavel Emelyanov
cf7b708c8d Make access to task's nsproxy lighter
When someone wants to deal with some other taks's namespaces it has to lock
the task and then to get the desired namespace if the one exists.  This is
slow on read-only paths and may be impossible in some cases.

E.g.  Oleg recently noticed a race between unshare() and the (sent for
review in cgroups) pid namespaces - when the task notifies the parent it
has to know the parent's namespace, but taking the task_lock() is
impossible there - the code is under write locked tasklist lock.

On the other hand switching the namespace on task (daemonize) and releasing
the namespace (after the last task exit) is rather rare operation and we
can sacrifice its speed to solve the issues above.

The access to other task namespaces is proposed to be performed
like this:

     rcu_read_lock();
     nsproxy = task_nsproxy(tsk);
     if (nsproxy != NULL) {
             / *
               * work with the namespaces here
               * e.g. get the reference on one of them
               * /
     } / *
         * NULL task_nsproxy() means that this task is
         * almost dead (zombie)
         * /
     rcu_read_unlock();

This patch has passed the review by Eric and Oleg :) and,
of course, tested.

[clg@fr.ibm.com: fix unshare()]
[ebiederm@xmission.com: Update get_net_ns_by_pid]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:37 -07:00
Serge E. Hallyn
b460cbc581 pid namespaces: define is_global_init() and is_container_init()
is_init() is an ambiguous name for the pid==1 check.  Split it into
is_global_init() and is_container_init().

A cgroup init has it's tsk->pid == 1.

A global init also has it's tsk->pid == 1 and it's active pid namespace
is the init_pid_ns.  But rather than check the active pid namespace,
compare the task structure with 'init_pid_ns.child_reaper', which is
initialized during boot to the /sbin/init process and never changes.

Changelog:

	2.6.22-rc4-mm2-pidns1:
	- Use 'init_pid_ns.child_reaper' to determine if a given task is the
	  global init (/sbin/init) process. This would improve performance
	  and remove dependence on the task_pid().

	2.6.21-mm2-pidns2:

	- [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc,
	  ppc,avr32}/traps.c for the _exception() call to is_global_init().
	  This way, we kill only the cgroup if the cgroup's init has a
	  bug rather than force a kernel panic.

[akpm@linux-foundation.org: fix comment]
[sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c]
[bunk@stusta.de: kernel/pid.c: remove unused exports]
[sukadev@us.ibm.com: Fix capability.c to work with threaded init]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Pavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:37 -07:00
Sukadev Bhattiprolu
88f21d8182 pid namespaces: rename child_reaper() function
Rename the child_reaper() function to task_child_reaper() to be similar to
other task_* functions and to distinguish the function from 'struct
pid_namspace.child_reaper'.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:37 -07:00
Pavel Emelianov
a47afb0f9d pid namespaces: round up the API
The set of functions process_session, task_session, process_group and
task_pgrp is confusing, as the names can be mixed with each other when looking
at the code for a long time.

The proposals are to
* equip the functions that return the integer with _nr suffix to
  represent that fact,
* and to make all functions work with task (not process) by making
  the common prefix of the same name.

For monotony the routines signal_session() and set_signal_session() are
replaced with task_session_nr() and set_task_session(), especially since they
are only used with the explicit task->signal dereference.

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:37 -07:00
Paul Menage
8793d854ed Task Control Groups: make cpusets a client of cgroups
Remove the filesystem support logic from the cpusets system and makes cpusets
a cgroup subsystem

The "cpuset" filesystem becomes a dummy filesystem; attempts to mount it get
passed through to the cgroup filesystem with the appropriate options to
emulate the old cpuset filesystem behaviour.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:36 -07:00
Paul Menage
b4f48b6363 Task Control Groups: add fork()/exit() hooks
This adds the necessary hooks to the fork() and exit() paths to ensure
that new children inherit their parent's cgroup assignments, and that
exiting processes release reference counts on their cgroups.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:36 -07:00
Alexey Dobriyan
42b2dd0a02 Shrink task_struct if CONFIG_FUTEX=n
robust_list, compat_robust_list, pi_state_list, pi_state_cache are
really used if futexes are on.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:55 -07:00
Oleg Nesterov
6db840fa78 exec: RT sub-thread can livelock and monopolize CPU on exec
de_thread() yields waiting for ->group_leader to be a zombie. This deadlocks
if an rt-prio execer shares the same cpu with ->group_leader. Change the code
to use ->group_exit_task/notify_count mechanics.

This patch certainly uglifies the code, perhaps someone can suggest something
better.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:54 -07:00
Oleg Nesterov
715015e8da wait_task_stopped/continued: remove unneeded p->signal != NULL check
The child was found on ->children list under tasklist_lock, it must have a
valid ->signal. __exit_signal() both removes the task from parent->children
and clears ->signal "atomically" under write_lock(tasklist).

Remove unneeded checks.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:52 -07:00
Oleg Nesterov
442a10cf9e wait_task_zombie: don't fight with non-existing race with a dying ptracee
The "p->exit_signal == -1 && p->ptrace == 0" check and the comment are
bogus.  We already did exactly the same check in eligible_child(), we did
not drop tasklist_lock since then, and both variables need
write_lock(tasklist) to be changed.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:51 -07:00
Oleg Nesterov
3ae4cbadf4 exit_notify: don't take tasklist for TIF_SIGPENDING re-targeting
->siglock provides enough protection to iterate over the thread group.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:51 -07:00
Oleg Nesterov
2f4e6e2a81 wait_task_zombie: fix 2/3 races vs forget_original_parent()
Two threads, T1 and T2.  T2 ptraces P, and P is not a child of ptracer's
thread group.  P exits and goes to TASK_ZOMBIE.

T1 does wait_task_zombie(P):

	P->exit_state = TASK_DEAD;
	...
	read_unlock(&tasklist_lock);

					T2 does exit(), takes tasklist,
					forget_original_parent() does
					__ptrace_unlink(P) but doesn't
					call do_notify_parent(P) because
					p->exit_state == EXIT_DEAD.

Now, P is not visible to our process: __ptrace_unlink() removed it from
->children. We should send notification to P->parent and release P if and
only if SIGCHLD is ignored.

And we have 3 bugs:

1. P->parent does do_wait() and gets -ECHILD (P is on ->parent->children,
   but its state is TASK_DEAD).

2. // wait_task_zombie() continues

	if (put_user(...)) {
		// TODO: is this safe?
		p->exit_state = EXIT_ZOMBIE;
		return;
	}

   we return without notification/release, task_struct leaked.

   Solution: ignore -EFAULT and proceed. It is an application's bug if
   we can't fill infop/stat_addr (in case of VM_FAULT_OOM we have much
   more problems).

3. // wait_task_zombie() continues

	if (p->real_parent != p->parent) {
		// Not taken, it was untraced'ed
		...
	}

	release_task(p);

   we released the task which we shouldn't.

   Solution: check ->real_parent != ->parent before, under tasklist_lock,
   but use ptrace_unlink() instead of __ptrace_unlink() to check ->ptrace.

This patch hopefully solves 2 and 3, the 1st bug will be fixed later, we need
some cleanups in forget_original_parent/reparent_thread.

However, the first race is very unlikely and not critical, so I hope it makes
sense to fix 1 and 2 for now.

4. Small cleanup: don't "restore" EXIT_ZOMBIE unless we know we are not going
   to realease the child.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:51 -07:00
Oleg Nesterov
407af46a96 wait_task_zombie: remove unneeded child->signal check
A zombie must have a valid ->signal, we are going to release it and
__exit_signal() starts with BUG_ON(!sig).

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:51 -07:00
Oleg Nesterov
84eb646b6e handle the multi-threaded init's exit() properly
With or without this patch, multi-threaded init's are not fully supported,
but do_exit() is completely wrong.  This becomes a real problem when we
support pid namespaces.

1. do_exit() panics when the main thread of /sbin/init exits. It should not
   until the whole thread group exits. Move the code below, under the
   "if (group_dead)" check.

   Note: this means that forget_original_parent() can use an already dead
   child_reaper()'s task_struct. This is OK for /sbin/init because

   	- do_wait() from alive sub-thread still can reap a zombie, we iterate
   	  over all sub-thread's ->children lists

   	- do_notify_parent() will wakeup some alive sub-thread because it sends
   	  the group-wide signal

   However, we should remove choose_new_parent()->BUG_ON(reaper->exit_state)
   for this.

2. We are playing games with ->nsproxy->pid_ns. This code is bogus today, and
   it has to be changed anyway when we really support pid namespaces, just
   remove it.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Roland McGrath <roland@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:51 -07:00
Oleg Nesterov
d2ee7198cc pi-futex: set PF_EXITING without taking ->pi_lock
It is a bit annoying that do_exit() takes ->pi_lock to set PF_EXITING.  All
we need is to synchronize with lookup_pi_state() which saw this task
without PF_EXITING under ->pi_lock.

Change do_exit() to use spin_unlock_wait().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:51 -07:00
Jesper Juhl
a9022e9cb9 Clean up duplicate includes in kernel/
This patch cleans up duplicate includes in
	kernel/

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:48 -07:00
Laurent Vivier
9ac52315d4 sched: guest CPU accounting: add guest-CPU /proc/<pid>/stat fields
like for cpustat, introduce the "gtime" (guest time of the task) and
"cgtime" (guest time of the task children) fields for the
tasks. Modify signal_struct and task_struct.

Modify /proc/<pid>/stat to display these new fields.

Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Acked-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-15 17:00:19 +02:00
Davide Libenzi
b8fceee17a signalfd simplification
This simplifies signalfd code, by avoiding it to remain attached to the
sighand during its lifetime.

In this way, the signalfd remain attached to the sighand only during
poll(2) (and select and epoll) and read(2).  This also allows to remove
all the custom "tsk == current" checks in kernel/signal.c, since
dequeue_signal() will only be called by "current".

I think this is also what Ben was suggesting time ago.

The external effect of this, is that a thread can extract only its own
private signals and the group ones.  I think this is an acceptable
behaviour, in that those are the signals the thread would be able to
fetch w/out signalfd.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-20 13:19:59 -07:00
Jonathan Lim
f2ab6d8889 Assign task_struct.exit_code before taskstats_exit()
taskstats.ac_exitcode is assigned to task_struct.exit_code in bacct_add_tsk()
through the following kernel function calls:

  do_exit()
    taskstats_exit()
      fill_pid()
        bacct_add_tsk()

The problem is that in do_exit(), task_struct.exit_code is set to 'code' only
after taskstats_exit() has been called.  So we need to move the assignment
before taskstats_exit().

Signed-off-by: Jonathan Lim <jlim@sgi.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-31 01:42:22 -07:00
Oleg Nesterov
247284481c Kill some obsolete sub-thread-ptrace stuff
There is a couple of subtle checks which were needed to handle ptracing from
the same thread group. This was deprecated a long ago, imho this code just
complicates the understanding.

And, the "->parent->signal->flags & SIGNAL_GROUP_EXIT" check in exit_notify()
is not right. SIGNAL_GROUP_EXIT can mean exec(), not exit_group(). This means
ptracer can lose a ptraced zombie on exec(). Minor problem, but still the bug.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-03 15:06:33 -07:00
Rafael J. Wysocki
0c1eecfb34 Freezer: avoid freezing kernel threads prematurely
Kernel threads should not have TIF_FREEZE set when user space processes are
being frozen, since otherwise some of them might be frozen prematurely.
To prevent this from happening we can (1) make exit_mm() unset TIF_FREEZE
unconditionally just after clearing tsk->mm and (2) make try_to_freeze_tasks()
check if p->mm is different from zero and PF_BORROWED_MM is unset in p->flags
when user space processes are to be frozen.

Namely, when user space processes are being frozen, we only should set
TIF_FREEZE for tasks that have p->mm different from NULL and don't have
PF_BORROWED_MM set in p->flags.  For this reason task_lock() must be used to
prevent try_to_freeze_tasks() from racing with use_mm()/unuse_mm(), in which
p->mm and p->flags.PF_BORROWED_MM are changed under task_lock(p).  Also, we
need to prevent the following scenario from happening:

* daemonize() is called by a task spawned from a user space code path
* freezer checks if the task has p->mm set and the result is positive
* task enters exit_mm() and clears its TIF_FREEZE
* freezer sets TIF_FREEZE for the task
* task calls try_to_freeze() and goes to the refrigerator, which is wrong at
  that point

This requires us to acquire task_lock(p) before p->flags.PF_BORROWED_MM and
p->mm are examined and release it after TIF_FREEZE is set for p (or it turns
out that TIF_FREEZE should not be set).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:42 -07:00
Rafael J. Wysocki
8314418629 Freezer: make kernel threads nonfreezable by default
Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves.  This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.

It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.

The patch causes all kernel threads to be nonfreezable by default (ie.  to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE.  It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear.  Additionally, it updates documentation to
describe the freezing of tasks more accurately.

[akpm@linux-foundation.org: build fixes]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:02 -07:00
Miloslav Trmac
522ed7767e Audit: add TTY input auditing
Add TTY input auditing, used to audit system administrator's actions.  This is
required by various security standards such as DCID 6/3 and PCI to provide
non-repudiation of administrator's actions and to allow a review of past
actions if the administrator seems to overstep their duties or if the system
becomes misconfigured for unknown reasons.  These requirements do not make it
necessary to audit TTY output as well.

Compared to an user-space keylogger, this approach records TTY input using the
audit subsystem, correlated with other audit events, and it is completely
transparent to the user-space application (e.g.  the console ioctls still
work).

TTY input auditing works on a higher level than auditing all system calls
within the session, which would produce an overwhelming amount of mostly
useless audit events.

Add an "audit_tty" attribute, inherited across fork ().  Data read from TTYs
by process with the attribute is sent to the audit subsystem by the kernel.
The audit netlink interface is extended to allow modifying the audit_tty
attribute, and to allow sending explanatory audit events from user-space (for
example, a shell might send an event containing the final command, after the
interactive command-line editing and history expansion is performed, which
might be difficult to decipher from the TTY input alone).

Because the "audit_tty" attribute is inherited across fork (), it would be set
e.g.  for sshd restarted within an audited session.  To prevent this, the
audit_tty attribute is cleared when a process with no open TTY file
descriptors (e.g.  after daemon startup) opens a TTY.

See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a
more detailed rationale document for an older version of this patch.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Miloslav Trmac <mitr@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:47 -07:00
Jeff Dike
e18eecb8b3 Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE
Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE.

This also adds UML support.

Tested on UML and i386.

[akpm@linux-foundation.org: cleanups, speedups, tweaks]
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:38 -07:00
Balbir Singh
172ba844a8 sched: update delay-accounting to use CFS's precise stats
update delay-accounting to use CFS's precise stats.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-07-09 18:52:00 +02:00
Ingo Molnar
e05606d330 sched: clean up the rt priority macros
clean up the rt priority macros, pointed out by Andrew Morton.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-07-09 18:51:59 +02:00
Ingo Molnar
f64f61145a sched: remove sched_exit()
remove sched_exit(): the elaborate dance of us trying to recover
timeslices given to child tasks never really worked.

CFS does not need it either.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-07-09 18:51:58 +02:00
Alexey Kuznetsov
778e9a9c3e pi-futex: fix exit races and locking problems
1. New entries can be added to tsk->pi_state_list after task completed
   exit_pi_state_list(). The result is memory leakage and deadlocks.

2. handle_mm_fault() is called under spinlock. The result is obvious.

3. results in self-inflicted deadlock inside glibc.
   Sometimes futex_lock_pi returns -ESRCH, when it is not expected
   and glibc enters to for(;;) sleep() to simulate deadlock. This problem
   is quite obvious and I think the patch is right. Though it looks like
   each "if" in futex_lock_pi() got some stupid special case "else if". :-)

4. sometimes futex_lock_pi() returns -EDEADLK,
   when nobody has the lock. The reason is also obvious (see comment
   in the patch), but correct fix is far beyond my comprehension.
   I guess someone already saw this, the chunk:

                        if (rt_mutex_trylock(&q.pi_state->pi_mutex))
                                ret = 0;

   is obviously from the same opera. But it does not work, because the
   rtmutex is really taken at this point: wake_futex_pi() of previous
   owner reassigned it to us. My fix works. But it looks very stupid.
   I would think about removal of shift of ownership in wake_futex_pi()
   and making all the work in context of process taking lock.

From: Thomas Gleixner <tglx@linutronix.de>

Fix 1) Avoid the tasklist lock variant of the exit race fix by adding
    an additional state transition to the exit code.

    This fixes also the issue, when a task with recursive segfaults
    is not able to release the futexes.

Fix 2) Cleanup the lookup_pi_state() failure path and solve the -ESRCH
    problem finally.

Fix 3) Solve the fixup_pi_state_owner() problem which needs to do the fixup
    in the lock protected section by using the in_atomic userspace access
    functions.

    This removes also the ugly lock drop / unqueue inside of fixup_pi_state()

Fix 4) Fix a stale lock in the error path of futex_wake_pi()

Added some error checks for verification.

The -EDEADLK problem is solved by the rtmutex fixups.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-08 17:23:34 -07:00
Roland McGrath
7bb44adef3 recalc_sigpending_tsk fixes
Steve Hawkes discovered a problem where recalc_sigpending_tsk was called in
do_sigaction but no signal_wake_up call was made, preventing later signals
from waking up blocked threads with TIF_SIGPENDING already set.

In fact, the few other calls to recalc_sigpending_tsk outside the signals
code are also subject to this problem in other race conditions.

This change makes recalc_sigpending_tsk private to the signals code.  It
changes the outside calls, as well as do_sigaction, to use the new
recalc_sigpending_and_wake instead.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: <Steve.Hawkes@motorola.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-23 20:14:12 -07:00
Davide Libenzi
fba2afaaec signal/timer/event: signalfd core
This patch series implements the new signalfd() system call.

I took part of the original Linus code (and you know how badly it can be
broken :), and I added even more breakage ;) Signals are fetched from the same
signal queue used by the process, so signalfd will compete with standard
kernel delivery in dequeue_signal().  If you want to reliably fetch signals on
the signalfd file, you need to block them with sigprocmask(SIG_BLOCK).  This
seems to be working fine on my Dual Opteron machine.  I made a quick test
program for it:

http://www.xmailserver.org/signafd-test.c

The signalfd() system call implements signal delivery into a file descriptor
receiver.  The signalfd file descriptor if created with the following API:

int signalfd(int ufd, const sigset_t *mask, size_t masksize);

The "ufd" parameter allows to change an existing signalfd sigmask, w/out going
to close/create cycle (Linus idea).  Use "ufd" == -1 if you want a brand new
signalfd file.

The "mask" allows to specify the signal mask of signals that we are interested
in.  The "masksize" parameter is the size of "mask".

The signalfd fd supports the poll(2) and read(2) system calls.  The poll(2)
will return POLLIN when signals are available to be dequeued.  As a direct
consequence of supporting the Linux poll subsystem, the signalfd fd can use
used together with epoll(2) too.

The read(2) system call will return a "struct signalfd_siginfo" structure in
the userspace supplied buffer.  The return value is the number of bytes copied
in the supplied buffer, or -1 in case of error.  The read(2) call can also
return 0, in case the sighand structure to which the signalfd was attached,
has been orphaned.  The O_NONBLOCK flag is also supported, and read(2) will
return -EAGAIN in case no signal is available.

If the size of the buffer passed to read(2) is lower than sizeof(struct
signalfd_siginfo), -EINVAL is returned.  A read from the signalfd can also
return -ERESTARTSYS in case a signal hits the process.  The format of the
struct signalfd_siginfo is, and the valid fields depends of the (->code &
__SI_MASK) value, in the same way a struct siginfo would:

struct signalfd_siginfo {
	__u32 signo;	/* si_signo */
	__s32 err;	/* si_errno */
	__s32 code;	/* si_code */
	__u32 pid;	/* si_pid */
	__u32 uid;	/* si_uid */
	__s32 fd;	/* si_fd */
	__u32 tid;	/* si_fd */
	__u32 band;	/* si_band */
	__u32 overrun;	/* si_overrun */
	__u32 trapno;	/* si_trapno */
	__s32 status;	/* si_status */
	__s32 svint;	/* si_int */
	__u64 svptr;	/* si_ptr */
	__u64 utime;	/* si_utime */
	__u64 stime;	/* si_stime */
	__u64 addr;	/* si_addr */
};

[akpm@linux-foundation.org: fix signalfd_copyinfo() on i386]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 08:29:36 -07:00
Sukadev Bhattiprolu
e713d0dab2 attach_pid() with struct pid parameter
attach_pid() currently takes a pid_t and then uses find_pid() to find the
corresponding struct pid.  Sometimes we already have the struct pid.  We can
then skip find_pid() if attach_pid() were to take a struct pid parameter.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: <containers@lists.osdl.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 08:29:35 -07:00
Eric Dumazet
6eaeeaba39 getrusage(): fill ru_inblock and ru_oublock fields if possible
If CONFIG_TASK_IO_ACCOUNTING is defined, we update io accounting counters for
each task.

This patch permits reporting of values using the well known getrusage()
syscall, filling ru_inblock and ru_oublock instead of null values.

As TASK_IO_ACCOUNTING currently counts bytes counts, we approximate blocks
count doing : nr_blocks = nr_bytes / 512

Example of use :
----------------------
After patch is applied, /usr/bin/time command can now give a good
approximation of IO that the process had to do.

$ /usr/bin/time grep tototo /usr/include/*
Command exited with non-zero status 1
0.00user 0.02system 0:02.11elapsed 1%CPU (0avgtext+0avgdata 0maxresident)k
24288inputs+0outputs (0major+259minor)pagefaults 0swaps

$ /usr/bin/time dd if=/dev/zero of=/tmp/testfile count=1000
1000+0 enregistrements lus
1000+0 enregistrements écrits
512000 octets (512 kB) copiés, 0,00326601 seconde, 157 MB/s
0.00user 0.00system 0:00.00elapsed 80%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+3000outputs (0major+299minor)pagefaults 0swaps

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 08:29:34 -07:00
Oleg Nesterov
10ab825bde change kernel threads to ignore signals instead of blocking them
Currently kernel threads use sigprocmask(SIG_BLOCK) to protect against
signals.  This doesn't prevent the signal delivery, this only blocks
signal_wake_up().  Every "killall -33 kthreadd" means a "struct siginfo"
leak.

Change kthreadd_setup() to set all handlers to SIG_IGN instead of blocking
them (make a new helper ignore_signals() for that).  If the kernel thread
needs some signal, it should use allow_signal() anyway, and in that case it
should not use CLONE_SIGHAND.

Note that we can't change daemonize() (should die!) in the same way,
because it can be used along with CLONE_SIGHAND.  This means that
allow_signal() still should unblock the signal to work correctly with
daemonize()ed threads.

However, disallow_signal() doesn't block the signal any longer but ignores
it.

NOTE: with or without this patch the kernel threads are not protected from
handle_stop_signal(), this seems harmless, but not good.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:53 -07:00
Eric W. Biederman
49d769d52e Change reparent_to_init to reparent_to_kthreadd
When a kernel thread calls daemonize, instead of reparenting the thread to
init reparent the thread to kthreadd next to the threads created by
kthread_create.

This is really just a stop gap until daemonize goes away, but it does
ensure no kernel threads are under init and they are all in one place that
is easy to find.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:53 -07:00
Randy Dunlap
e63340ae6b header cleaning: don't include smp_lock.h when not used
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:07 -07:00
Roland McGrath
7324328446 Return EPERM not ECHILD on security_task_wait failure
wait* syscalls return -ECHILD even when an individual PID of a live child
was requested explicitly, when security_task_wait denies the operation.
This means that something like a broken SELinux policy can produce an
unexpected failure that looks just like a bug with wait or ptrace or
something.

This patch makes do_wait return -EACCES (or other appropriate error returned
from security_task_wait() instead of -ECHILD if some children were ruled out
solely because security_task_wait failed.

[jmorris@namei.org: switch error code to EACCES]
Signed-off-by: Roland McGrath <roland@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:12:57 -07:00
Eric W. Biederman
14e9d5730a [PATCH] pid: Properly detect orphaned process groups in exit_notify
In commit 0475ac0845 when converting the
orphaned process group handling to use struct pid I made a small
mistake.  I accidentally replaced an == with a !=.

Besides just being a dumb thing to do apparently this has a bad side
effect.  The improper orphaned process group detection causes kwin to
die after a suspend/resume cycle.

I'm amazed this patch has been around as long as it has without anyone
else noticing something funny going on.

And the following people deserve credit for spotting and helping
to reproduce this.

Thanks to: Sid Boyce <g3vbv@blueyonder.co.uk>
Thanks to: "Michael Wu"

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-29 08:16:23 -07:00
Eric W. Biederman
3e7cd6c413 [PATCH] pid: replace is_orphaned_pgrp with is_current_pgrp_orphaned
Every call to is_orphaned_pgrp passed in process_group(current) which is racy
with respect to another thread changing our process group.  It didn't bite us
because we were dealing with integers and the worse we would get would be a
stale answer.

In switching the checks to use struct pid to be a little more efficient and
prepare the way for pid namespaces this race became apparent.

So I simplified the calls to the more specialized is_current_pgrp_orphaned so
I didn't have to worry about making logic changes to avoid the race.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:32 -08:00
Eric W. Biederman
0475ac0845 [PATCH] pid: use struct pid for talking about process groups in exitc
Modify has_stopped_jobs and will_become_orphan_pgrp to use struct pid based
process groups.  This reduces the number of hash tables looks ups and paves
the way for multiple pid spaces.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:32 -08:00
Eric W. Biederman
04a2e6a5cb [PATCH] pid: make session_of_pgrp use struct pid instead of pid_t
To properly implement a pid namespace I need to deal exclusively in terms of
struct pid, because pid_t values become ambiguous.

To this end session_of_pgrp is transformed to take and return a struct pid
pointer.  To avoid the need to worry about reference counting I now require my
caller to hold the appropriate locks.  Leaving callers repsonsible for
increasing the reference count if they need access to the result outside of
the locks.

Since session_of_pgrp currently only has one caller and that caller simply
uses only test the result for equality with another process group, the locking
change means I don't actually have to acquire the tasklist_lock at all.

tiocspgrp is also modified to take and release the lock.  The logic there is a
little more complicated but nothing I won't need when I convert pgrp of a tty
to a struct pid pointer.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:31 -08:00
Ingo Molnar
944be0b224 [PATCH] close_files(): add scheduling point
close_files() can sometimes take long enough to trigger the soft lockup
detector.

Cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:30 -08:00
Robert P. J. Day
72fd4a35a8 [PATCH] Numerous fixes to kernel-doc info in source files.
A variety of (mostly) innocuous fixes to the embedded kernel-doc content in
source files, including:

  * make multi-line initial descriptions single line
  * denote some function names, constants and structs as such
  * change erroneous opening '/*' to '/**' in a few places
  * reword some text for clarity

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:32 -08:00
Serge E. Hallyn
0f2452855d [PATCH] namespaces: fix task exit disaster
This is based on a patch by Eric W.  Biederman, who pointed out that pid
namespaces are still fake, and we only have one ever active.

So for the time being, we can modify any code which could access
tsk->nsproxy->pid_ns during task exit to just use &init_pid_ns instead,
and move the exit_task_namespaces call in do_exit() back above
exit_notify(), so that an exiting nfs server has a valid tsk->sighand to
work with.

Long term, pulling pid_ns out of nsproxy might be the cleanest solution.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

[ Eric's patch fixed to take care of free_pid() too ]

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-30 13:40:36 -08:00
Linus Torvalds
444f378b23 Revert "[PATCH] namespaces: fix exit race by splitting exit"
This reverts commit 7a238fcba0 in
preparation for a better and simpler fix proposed by Eric Biederman
(and fixed up by Serge Hallyn)

Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-30 13:35:18 -08:00
Serge E. Hallyn
7a238fcba0 [PATCH] namespaces: fix exit race by splitting exit
Fix exit race by splitting the nsproxy putting into two pieces.  First
piece reduces the nsproxy refcount.  If we dropped the last reference, then
it puts the mnt_ns, and returns the nsproxy as a hint to the caller.  Else
it returns NULL.  The second piece of exiting task namespaces sets
tsk->nsproxy to NULL, and drops the references to other namespaces and
frees the nsproxy only if an nsproxy was passed in.

A little awkward and should probably be reworked, but hopefully it fixes
the NFS oops.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Daniel Hokka Zakrisson <daniel@hozac.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-30 08:26:44 -08:00
Oleg Nesterov
241ceee0b4 [PATCH] restore ->pdeath_signal behaviour
Commit b2b2cbc4b2 introduced a user-
visible change: ->pdeath_signal is sent only when the entire thread
group exits.

While this change is imho good, it may break things.  So restore the
old behaviour for now.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
To: Albert Cahalan <acahalan@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Linus Torvalds <torvalds@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Qi Yong <qiyong@fc-cn.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-31 14:41:18 -08:00
Eric W. Biederman
b2b2cbc4b2 [PATCH] Fix reparenting to the same thread group. (take 2)
This patch fixes the case when we reparent to a different thread in the
same thread group.  This modifies the code so that we do not send
signals and do not change the signal to send to SIGCHLD unless we have
change the thread group of our parents.  It also suppresses sending
pdeath_sig in this cas as well since the result of geppid doesn't
change.

Thanks to Oleg for spotting my bug of only fixing this for non-ptraced
tasks.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Albert Cahalan <acahalan@gmail.com>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Coywolf Qi Hunt <qiyong@fc-cn.com>
Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-22 09:03:41 -08:00
Vadim Lobanov
01b2d93ca4 [PATCH] fdtable: Provide free_fdtable() wrapper
Christoph Hellwig has expressed concerns that the recent fdtable changes
expose the details of the RCU methodology used to release no-longer-used
fdtable structures to the rest of the kernel.  The trivial patch below
addresses these concerns by introducing the appropriate free_fdtable()
calls, which simply wrap the release RCU usage.  Since free_fdtable() is a
one-liner, it makes sense to promote it to an inline helper.

Signed-off-by: Vadim Lobanov <vlobanov@speakeasy.net>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-22 08:55:50 -08:00
Vadim Lobanov
4fd45812cb [PATCH] fdtable: Remove the free_files field
An fdtable can either be embedded inside a files_struct or standalone (after
being expanded).  When an fdtable is being discarded after all RCU references
to it have expired, we must either free it directly, in the standalone case,
or free the files_struct it is contained within, in the embedded case.

Currently the free_files field controls this behavior, but we can get rid of
it entirely, as all the necessary information is already recorded.  We can
distinguish embedded and standalone fdtables using max_fds, and if it is
embedded we can divine the relevant files_struct using container_of().

Signed-off-by: Vadim Lobanov <vlobanov@speakeasy.net>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-10 09:57:22 -08:00
Vadim Lobanov
bbea9f6966 [PATCH] fdtable: Make fdarray and fdsets equal in size
Currently, each fdtable supports three dynamically-sized arrays of data: the
fdarray and two fdsets.  The code allows the number of fds supported by the
fdarray (fdtable->max_fds) to differ from the number of fds supported by each
of the fdsets (fdtable->max_fdset).

In practice, it is wasteful for these two sizes to differ: whenever we hit a
limit on the smaller-capacity structure, we will reallocate the entire fdtable
and all the dynamic arrays within it, so any delta in the memory used by the
larger-capacity structure will never be touched at all.

Rather than hogging this excess, we shouldn't even allocate it in the first
place, and keep the capacities of the fdarray and the fdsets equal.  This
patch removes fdtable->max_fdset.  As an added bonus, most of the supporting
code becomes simpler.

Signed-off-by: Vadim Lobanov <vlobanov@speakeasy.net>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-10 09:57:22 -08:00
Oleg Nesterov
62dfb5541a [PATCH] session_of_pgrp: kill unnecessary do_each_task_pid(PIDTYPE_PGID)
All members of the process group have the same sid and it can't be == 0.

NOTE: this code (and a similar one in sys_setpgid) was needed because it
was possibe to have ->session == 0. It's not possible any longer since

	[PATCH] pidhash: don't use zero pids
	Commit: c7c6464117

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:52 -08:00
Sukadev Bhattiprolu
84d737866e [PATCH] add child reaper to pid_namespace
Add a per pid_namespace child-reaper.  This is needed so processes are reaped
within the same pid space and do not spill over to the parent pid space.  Its
also needed so containers preserve existing semantic that pid == 1 would reap
orphaned children.

This is based on Eric Biederman's patch: http://lkml.org/lkml/2006/2/6/285

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:52 -08:00
Kirill Korotaev
6b3286ed11 [PATCH] rename struct namespace to struct mnt_namespace
Rename 'struct namespace' to 'struct mnt_namespace' to avoid confusion with
other namespaces being developped for the containers : pid, uts, ipc, etc.
'namespace' variables and attributes are also renamed to 'mnt_ns'

Signed-off-by: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:51 -08:00
Cedric Le Goater
1ec320afdc [PATCH] add process_session() helper routine: deprecate old field
Add an anonymous union and ((deprecated)) to catch direct usage of the
session field.

[akpm@osdl.org: fix various missed conversions]
[jdike@addtoit.com: fix UML bug]
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:51 -08:00
Cedric Le Goater
937949d9ed [PATCH] add process_session() helper routine
Replace occurences of task->signal->session by a new process_session() helper
routine.

It will be useful for pid namespaces to abstract the session pid number.

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:51 -08:00
Oleg Nesterov
ae424ae4b5 [PATCH] make set_special_pids() static
Make set_special_pids() static, the only caller is daemonize().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:38 -08:00
Peter Zijlstra
24ec839c43 [PATCH] tty: ->signal->tty locking
Fix the locking of signal->tty.

Use ->sighand->siglock to protect ->signal->tty; this lock is already used
by most other members of ->signal/->sighand.  And unless we are 'current'
or the tasklist_lock is held we need ->siglock to access ->signal anyway.

(NOTE: sys_unshare() is broken wrt ->sighand locking rules)

Note that tty_mutex is held over tty destruction, so while holding
tty_mutex any tty pointer remains valid.  Otherwise the lifetime of ttys
are governed by their open file handles.  This leaves some holes for tty
access from signal->tty (or any other non file related tty access).

It solves the tty SLAB scribbles we were seeing.

(NOTE: the change from group_send_sig_info to __group_send_sig_info needs to
       be examined by someone familiar with the security framework, I think
       it is safe given the SEND_SIG_PRIV from other __group_send_sig_info
       invocations)

[schwidefsky@de.ibm.com: 3270 fix]
[akpm@osdl.org: various post-viro fixes]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Alan Cox <alan@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jan Kara <jack@ucw.cz>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:38 -08:00
Oleg Nesterov
115085ea07 [PATCH] taskstats: cleanup do_exit() path
do_exit:
	taskstats_exit_alloc()
	...
	taskstats_exit_send()
	taskstats_exit_free()

I think this is not good, let it be a single function exported to the core
kernel, taskstats_exit(), which does alloc + send + free itself.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:34 -08:00
Oleg Nesterov
093a8e8aec [PATCH] taskstats_tgid_free: fix usage
taskstats_tgid_free() is called on copy_process's error path. This is wrong.

	IF (clone_flags & CLONE_THREAD)
		We should not clear ->signal->taskstats, current uses it,
		it probably has a valid accumulated info.
	ELSE
		taskstats_tgid_init() set ->signal->taskstats = NULL,
		there is nothing to free.

Move the callsite to __exit_signal(). We don't need any locking, entire
thread group is exiting, nobody should have a reference to soon to be
released ->signal.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-28 11:30:54 -07:00
Cedric Le Goater
fab413a334 [PATCH] namespaces: exit_task_namespaces() invalidates nsproxy
exit_task_namespaces() has replaced the former exit_namespace().  It
invalidates task->nsproxy and associated namespaces.  This is an issue for
the (futur) pid namespace which is required to be valid in exit_notify().

This patch moves exit_task_namespaces() after exit_notify() to keep nsproxy
valid.

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-02 07:57:21 -07:00
Serge E. Hallyn
1651e14e28 [PATCH] namespaces: incorporate fs namespace into nsproxy
This moves the mount namespace into the nsproxy.  The mount namespace count
now refers to the number of nsproxies point to it, rather than the number of
tasks.  As a result, the unshare_namespace() function in kernel/fork.c no
longer checks whether it is being shared.

Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-02 07:57:20 -07:00
Serge E. Hallyn
ab516013ad [PATCH] namespaces: add nsproxy
This patch adds a nsproxy structure to the task struct.  Later patches will
move the fs namespace pointer into this structure, and introduce a new utsname
namespace into the nsproxy.

The vserver and openvz functionality, then, would be implemented in large part
by virtualizing/isolating more and more resources into namespaces, each
contained in the nsproxy.

[akpm@osdl.org: build fix]
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-02 07:57:20 -07:00
Jay Lan
8f0ab51479 [PATCH] csa: convert CONFIG tag for extended accounting routines
There were a few accounting data/macros that are used in CSA but are #ifdef'ed
inside CONFIG_BSD_PROCESS_ACCT.  This patch is to change those ifdef's from
CONFIG_BSD_PROCESS_ACCT to CONFIG_TASK_XACCT.  A few defines are moved from
kernel/acct.c and include/linux/acct.h to kernel/tsacct.c and
include/linux/tsacct_kern.h.

Signed-off-by: Jay Lan <jlan@sgi.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Chris Sturtivant <csturtiv@sgi.com>
Cc: Tony Ernst <tee@sgi.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 00:39:29 -07:00
David Howells
0d67a46df0 [PATCH] BLOCK: Remove duplicate declaration of exit_io_context() [try #6]
Remove the duplicate declaration of exit_io_context() from linux/sched.h.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:31:20 +02:00
Oleg Nesterov
c394cc9fbb [PATCH] introduce TASK_DEAD state
I am not sure about this patch, I am asking Ingo to take a decision.

task_struct->state == EXIT_DEAD is a very special case, to avoid a confusion
it makes sense to introduce a new state, TASK_DEAD, while EXIT_DEAD should
live only in ->exit_state as documented in sched.h.

Note that this state is not visible to user-space, get_task_state() masks off
unsuitable states.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:21 -07:00
Oleg Nesterov
55a101f8f7 [PATCH] kill PF_DEAD flag
After the previous change (->flags & PF_DEAD) <=> (->state == EXIT_DEAD), we
don't need PF_DEAD any longer.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:20 -07:00
Oleg Nesterov
29b8849216 [PATCH] set EXIT_DEAD state in do_exit(), not in schedule()
schedule() checks PF_DEAD on every context switch and sets ->state = EXIT_DEAD
to ensure that the exiting task will be deactivated.  Note that this EXIT_DEAD
is in fact a "random" value, we can use any bit except normal TASK_XXX values.

It is better to set this state in do_exit() along with PF_DEAD flag and remove
that check in schedule().

We are safe wrt concurrent try_to_wake_up() (for example ptrace, tkill), it
can not change task's ->state: the 'state' argument of try_to_wake_up() can't
have EXIT_DEAD bit.  And in case when try_to_wake_up() sees a stale value of
->state == TASK_RUNNING it will do nothing.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:20 -07:00
Oleg Nesterov
1c573afebc [PATCH] reparent_to_init(): use has_rt_policy()
Remove open-coded has_rt_policy(), no changes in kernel/exit.o

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:18 -07:00
Alan Cox
54306cf04c [PATCH] exit: fix crash case
If we are going to BUG() not panic() here then we should cover the case of
the BUG being compiled out

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:16 -07:00
Roland McGrath
b9ecb2bd5d [PATCH] has_stopped_jobs() cleanup
This check has been obsolete since the introduction of TASK_TRACED.  Now
TASK_STOPPED always means job control stop.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:15 -07:00
Sukadev Bhattiprolu
f400e198b2 [PATCH] pidspace: is_init()
This is an updated version of Eric Biederman's is_init() patch.
(http://lkml.org/lkml/2006/2/6/280).  It applies cleanly to 2.6.18-rc3 and
replaces a few more instances of ->pid == 1 with is_init().

Further, is_init() checks pid and thus removes dependency on Eric's other
patches for now.

Eric's original description:

	There are a lot of places in the kernel where we test for init
	because we give it special properties.  Most  significantly init
	must not die.  This results in code all over the kernel test
	->pid == 1.

	Introduce is_init to capture this case.

	With multiple pid spaces for all of the cases affected we are
	looking for only the first process on the system, not some other
	process that has pid == 1.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: <lxc-devel@lists.sourceforge.net>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:12 -07:00
Kirill Korotaev
3b9b8ab65d [PATCH] Fix unserialized task->files changing
Fixed race on put_files_struct on exec with proc.  Restoring files on
current on error path may lead to proc having a pointer to already kfree-d
files_struct.

->files changing at exit.c and khtread.c are safe as exit_files() makes all
things under lock.

Found during OpenVZ stress testing.

[akpm@osdl.org: add export]
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:12 -07:00
Oleg Nesterov
3b6362b833 [PATCH] eligible_child: remove an obsolete ->tgid check
It is not possible to find a sub-thread in ->children/->ptrace_children
lists, ptrace_attach() does not allow to attach to sub-threads.

Even if it was possible to ptrace the task from the same thread group,
we can't allow to release ->group_leader while there are others (ptracer)
threads in the same group.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-02 14:51:27 -07:00
Shailabh Nagar
35df17c57c [PATCH] task delay accounting fixes
Cleanup allocation and freeing of tsk->delays used by delay accounting.
This solves two problems reported for delay accounting:

1. oops in __delayacct_blkio_ticks
http://www.uwsg.indiana.edu/hypermail/linux/kernel/0608.2/1844.html

Currently tsk->delays is getting freed too early in task exit which can
cause a NULL tsk->delays to get accessed via reading of /proc/<tgid>/stats.
 The patch fixes this problem by freeing tsk->delays closer to when
task_struct itself is freed up.  As a result, it also eliminates the use of
tsk->delays_lock which was only being used (inadequately) to safeguard
access to tsk->delays while a task was exiting.

2. Possible memory leak in kernel/delayacct.c
http://www.uwsg.indiana.edu/hypermail/linux/kernel/0608.2/1389.html

The patch cleans up tsk->delays allocations after a bad fork which was
missing earlier.

The patch has been tested to fix the problems listed above and stress
tested with rapid calls to delay accounting's taskstats command interface
(which is the other path that can access the same data, besides the /proc
interface causing the oops above).

Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-01 11:39:08 -07:00
Shailabh Nagar
f9fd8914c1 [PATCH] per-task delay accounting taskstats interface: control exit data through cpumasks
On systems with a large number of cpus, with even a modest rate of tasks
exiting per cpu, the volume of taskstats data sent on thread exit can
overflow a userspace listener's buffers.

One approach to avoiding overflow is to allow listeners to get data for a
limited and specific set of cpus.  By scaling the number of listeners
and/or the cpus they monitor, userspace can handle the statistical data
overload more gracefully.

In this patch, each listener registers to listen to a specific set of cpus
by specifying a cpumask.  The interest is recorded per-cpu.  When a task
exits on a cpu, its taskstats data is unicast to each listener interested
in that cpu.

Thanks to Andrew Morton for pointing out the various scalability and
general concerns of previous attempts and for suggesting this design.

[akpm@osdl.org: build fix]
Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-14 21:53:57 -07:00
Shailabh Nagar
ad4ecbcba7 [PATCH] delay accounting taskstats interface send tgid once
Send per-tgid data only once during exit of a thread group instead of once
with each member thread exit.

Currently, when a thread exits, besides its per-tid data, the per-tgid data
of its thread group is also sent out, if its thread group is non-empty.
The per-tgid data sent consists of the sum of per-tid stats for all
*remaining* threads of the thread group.

This patch modifies this sending in two ways:

- the per-tgid data is sent only when the last thread of a thread group
  exits.  This cuts down heavily on the overhead of sending/receiving
  per-tgid data, especially when other exploiters of the taskstats
  interface aren't interested in per-tgid stats

- the semantics of the per-tgid data sent are changed.  Instead of being
  the sum of per-tid data for remaining threads, the value now sent is the
  true total accumalated statistics for all threads that are/were part of
  the thread group.

The patch also addresses a minor issue where failure of one accounting
subsystem to fill in the taskstats structure was causing the send of
taskstats to not be sent at all.

The patch has been tested for stability and run cerberus for over 4 hours
on an SMP.

[akpm@osdl.org: bugfixes]
Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-14 21:53:57 -07:00
Shailabh Nagar
c757249af1 [PATCH] per-task-delay-accounting: taskstats interface
Create a "taskstats" interface based on generic netlink (NETLINK_GENERIC
family), for getting statistics of tasks and thread groups during their
lifetime and when they exit.  The interface is intended for use by multiple
accounting packages though it is being created in the context of delay
accounting.

This patch creates the interface without populating the fields of the data
that is sent to the user in response to a command or upon the exit of a task.
Each accounting package interested in using taskstats has to provide an
additional patch to add its stats to the common structure.

[akpm@osdl.org: cleanups, Kconfig fix]
Signed-off-by: Shailabh Nagar <nagar@us.ibm.com>
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Peter Chubb <peterc@gelato.unsw.edu.au>
Cc: Erich Focht <efocht@ess.nec.de>
Cc: Levent Serinol <lserinol@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-14 21:53:56 -07:00
Shailabh Nagar
ca74e92b46 [PATCH] per-task-delay-accounting: setup
Initialization code related to collection of per-task "delay" statistics which
measure how long it had to wait for cpu, sync block io, swapping etc.  The
collection of statistics and the interface are in other patches.  This patch
sets up the data structures and allows the statistics collection to be
disabled through a kernel boot parameter.

Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Peter Chubb <peterc@gelato.unsw.edu.au>
Cc: Erich Focht <efocht@ess.nec.de>
Cc: Levent Serinol <lserinol@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-14 21:53:56 -07:00
Ingo Molnar
36c8b58689 [PATCH] sched: cleanup, remove task_t, convert to struct task_struct
cleanup: remove task_t and convert all the uses to struct task_struct. I
introduced it for the scheduler anno and it was a mistake.

Conversion was mostly scripted, the result was reviewed and all
secondary whitespace and style impact (if any) was fixed up by hand.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:11 -07:00
Ingo Molnar
9a11b49a80 [PATCH] lockdep: better lock debugging
Generic lock debugging:

 - generalized lock debugging framework. For example, a bug in one lock
   subsystem turns off debugging in all lock subsystems.

 - got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from
   the mutex/rtmutex debugging code: it caused way too much prototype
   hackery, and lockdep will give the same information anyway.

 - ability to do silent tests

 - check lock freeing in vfree too.

 - more finegrained debugging options, to allow distributions to
   turn off more expensive debugging features.

There's no separate 'held mutexes' list anymore - but there's a 'held locks'
stack within lockdep, which unifies deadlock detection across all lock
classes.  (this is independent of the lockdep validation stuff - lockdep first
checks whether we are holding a lock already)

Here are the current debugging options:

CONFIG_DEBUG_MUTEXES=y
CONFIG_DEBUG_LOCK_ALLOC=y

which do:

 config DEBUG_MUTEXES
          bool "Mutex debugging, basic checks"

 config DEBUG_LOCK_ALLOC
         bool "Detect incorrect freeing of live mutexes"

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:01 -07:00
Jörn Engel
6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Ingo Molnar
c87e2837be [PATCH] pi-futex: futex_lock_pi/futex_unlock_pi support
This adds the actual pi-futex implementation, based on rt-mutexes.

[dino@in.ibm.com: fix an oops-causing race]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Dinakar Guniguntala <dino@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 17:32:47 -07:00
Ingo Molnar
e7eebaf6a8 [PATCH] pi-futex: rt mutex debug
Runtime debugging functionality for rt-mutexes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 17:32:47 -07:00
Eric W. Biederman
48e6484d49 [PATCH] proc: Rewrite the proc dentry flush on exit optimization
To keep the dcache from filling up with dead /proc entries we flush them on
process exit.  However over the years that code has gotten hairy with a
dentry_pointer and a lock in task_struct and misdocumented as a correctness
feature.

I have rewritten this code to look and see if we have a corresponding entry in
the dcache and if so flush it on process exit.  This removes the extra fields
in the task_struct and allows me to trivially handle the case of a
/proc/<tgid>/task/<pid> entry as well as the current /proc/<pid> entries.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:24 -07:00
KaiGai Kohei
f6ec29a42d [PATCH] pacct: avoidance to refer the last thread as a representation of the process
When pacct facility generate an 'ac_flag' field in accounting record, it
refers a task_struct of the thread which died last in the process.  But any
other task_structs are ignored.

Therefore, pacct facility drops ASU flag even if root-privilege operations are
used by any other threads except the last one.  In addition, AFORK flag is
always set when the thread of group-leader didn't die last, although this
process has called execve() after fork().

We have a same matter in ac_exitcode.  The recorded ac_exitcode is an exit
code of the last thread in the process.  There is a possibility this exitcode
is not the group leader's one.
2006-06-25 10:01:25 -07:00
KaiGai Kohei
0e4648141a [PATCH] pacct: add pacct_struct to fix some pacct bugs.
The pacct facility need an i/o operation when an accounting record is
generated.  There is a possibility to wake OOM killer up.  If OOM killer is
activated, it kills some processes to make them release process memory
regions.

But acct_process() is called in the killed processes context before calling
exit_mm(), so those processes cannot release own memory.  In the results, any
processes stop in this point and it finally cause a system stall.
2006-06-25 10:01:25 -07:00
Anton Blanchard
2aa92581fb [PATCH] Link error when futexes are disabled on 64bit architectures
If futexes are disabled we fail to link on ppc64.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-25 10:01:17 -07:00
Adrian Bunk
83cc5ed3c4 [PATCH] kernel/sys.c: cleanups
- proper prototypes for the following functions:
  - ctrl_alt_del()  (in include/linux/reboot.h)
  - getrusage()     (in include/linux/resource.h)
- make the following needlessly global functions static:
  - kernel_restart_prepare()
  - kernel_kexec()

[akpm@osdl.org: compile fix]
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-25 10:01:06 -07:00
Eric Sesterhenn
125e18745f [PATCH] More BUG_ON conversion
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Acked-by: "Salyzyn, Mark" <mark_salyzyn@adaptec.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:43:08 -07:00
Oleg Nesterov
30f1e3dd8c [PATCH] run_posix_cpu_timers: remove a bogus BUG_ON()
do_exit() clears ->it_##clock##_expires, but nothing prevents
another cpu to attach the timer to exiting process after that.
arm_timer() tries to protect against this race, but the check
is racy.

After exit_notify() does 'write_unlock_irq(&tasklist_lock)' and
before do_exit() calls 'schedule() local timer interrupt can find
tsk->exit_state != 0. If that state was EXIT_DEAD (or another cpu
does sys_wait4) interrupted task has ->signal == NULL.

At this moment exiting task has no pending cpu timers, they were
cleanuped in __exit_signal()->posix_cpu_timers_exit{,_group}(),
so we can just return from irq.

John Stultz recently confirmed this bug, see

	http://marc.theaimsgroup.com/?l=linux-kernel&m=115015841413687

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-17 10:52:13 -07:00
Al Viro
fa84cb935d [PATCH] move call of audit_free() into do_exit()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-05-01 06:06:13 -04:00
Eric W. Biederman
5e85d4abe3 [PATCH] task: Make task list manipulations RCU safe
While we can currently walk through thread groups, process groups, and
sessions with just the rcu_read_lock, this opens the door to walking the
entire task list.

We already have all of the other RCU guarantees so there is no cost in
doing this, this should be enough so that proc can stop taking the
tasklist lock during readdir.

prev_task was killed because it has no users, and using it will miss new
tasks when doing an rcu traversal.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-19 09:13:49 -07:00
Jens Axboe
b92ce55893 [PATCH] splice: add direct fd <-> fd splicing support
It's more efficient for sendfile() emulation. Basically we cache an
internal private pipe and just use that as the intermediate area for
pages. Direct splicing is not available from sys_splice(), it is only
meant to be used for sendfile() emulation.

Additional patch from Ingo Molnar to avoid the PIPE_BUFFERS loop at
exit for the normal fast path.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-04-11 13:52:07 +02:00
Eric W. Biederman
8c7904a00b [PATCH] task: RCU protect task->usage
A big problem with rcu protected data structures that are also reference
counted is that you must jump through several hoops to increase the reference
count.  I think someone finally implemented atomic_inc_not_zero(&count) to
automate the common case.  Unfortunately this means you must special case the
rcu access case.

When data structures are only visible via rcu in a manner that is not
determined by the reference count on the object (i.e.  tasks are visible until
their zombies are reaped) there is a much simpler technique we can employ.
Simply delaying the decrement of the reference count until the rcu interval is
over.

What that means is that the proc code that looks up a task and later
wants to sleep can now do:

rcu_read_lock();
task = find_task_by_pid(some_pid);
if (task) {
	get_task_struct(task);
}
rcu_read_unlock();

The effect on the rest of the kernel is that put_task_struct becomes cheaper
and immediate, and in the case where the task has been reaped it frees the
task immediate instead of unnecessarily waiting an until the rcu interval is
over.

Cleanup of task_struct does not happen when its reference count drops to
zero, instead cleanup happens when release_task is called.  Tasks can only
be looked up via rcu before release_task is called.  All rcu protected
members of task_struct are freed by release_task.

Therefore we can move call_rcu from put_task_struct into release_task.  And
we can modify release_task to not immediately release the reference count
but instead have it call put_task_struct from the function it gives to
call_rcu.

The end result:

- get_task_struct is safe in an rcu context where we have just looked
  up the task.

- put_task_struct() simplifies into its old pre rcu self.

This reorganization also makes put_task_struct uncallable from modules as
it is not exported but it does not appear to be called from any modules so
this should not be an issue, and is trivially fixed.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-31 12:18:59 -08:00
Oleg Nesterov
a7e5328a06 [PATCH] cleanup __exit_signal->cleanup_sighand path
Move 'tsk->sighand = NULL' from cleanup_sighand() to __exit_signal().  This
makes the exit path more understandable and allows us to do
cleanup_sighand() outside of ->siglock protected section.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:44 -08:00
Oleg Nesterov
47e65328a7 [PATCH] pids: kill PIDTYPE_TGID
This patch kills PIDTYPE_TGID pid_type thus saving one hash table in
kernel/pid.c and speeding up subthreads create/destroy a bit.  It is also a
preparation for the further tref/pids rework.

This patch adds 'struct list_head thread_group' to 'struct task_struct'
instead.

We don't detach group leader from PIDTYPE_PID namespace until another
thread inherits it's ->pid == ->tgid, so we are safe wrt premature
free_pidmap(->tgid) call.

Currently there are no users of find_task_by_pid_type(PIDTYPE_TGID).
Should the need arise, we can use find_task_by_pid()->group_leader.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-By: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:44 -08:00
Oleg Nesterov
aacc90944d [PATCH] do_group_exit: don't take tasklist_lock
do_group_exit() takes tasklist_lock for zap_other_threads(), this is unneeded
now.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:43 -08:00
Oleg Nesterov
5876700cd3 [PATCH] do __unhash_process() under ->siglock
This patch moves __unhash_process() call from realease_task() to
__exit_signal(), so __detach_pid() is called with ->siglock held.

This means we don't need tasklist_lock to iterate over thread group anymore:

	copy_process() was already changed to do attach_pid()
	under ->siglock.

	Eric's "pidhash-kill-switch_exec_pids.patch" from -mm
	changed de_thread() so it doesn't touch PIDTYPE_TGID.

NOTE: de_thread() still needs some attention.  It still changes task->pid
lockless.  Taking ->sighand.siglock here allows to do more tasklist_lock
removals.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:43 -08:00
Oleg Nesterov
35f5cad8c4 [PATCH] revert "Optimize sys_times for a single thread process"
This patch reverts 'CONFIG_SMP && thread_group_empty()' optimization in
sys_times().  The reason is that the next patch breaks memory ordering which
is needed for that optimization.

tasklist_lock in sys_times() will be eliminated completely by further patch.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:43 -08:00
Oleg Nesterov
6a14c5c9da [PATCH] move __exit_signal() to kernel/exit.c
__exit_signal() is private to release_task() now.  I think it is better to
make it static in kernel/exit.c and export flush_sigqueue() instead - this
function is much more simple and straightforward.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:43 -08:00
Oleg Nesterov
1f09f9749c [PATCH] release_task: replace open-coded ptrace_unlink()
Use ptrace_unlink() instead of open-coding.  No changes in kernel/exit.o

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:41 -08:00
Oleg Nesterov
6ac781b11a [PATCH] reparent_thread: use remove_parent/add_parent
Use remove_parent/add_parent instead of open coding.

No changes in kernel/exit.o

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:41 -08:00
Oleg Nesterov
73b9ebfe12 [PATCH] pidhash: don't count idle threads
fork_idle() does unhash_process() just after copy_process().  Contrary,
boot_cpu's idle thread explicitely registers itself for each pid_type with nr
= 0.

copy_process() already checks p->pid != 0 before process_counts++, I think we
can just skip attach_pid() calls and job control inits for idle threads and
kill unhash_process().  We don't need to cleanup ->proc_dentry in fork_idle()
because with this patch idle threads are never hashed in
kernel/pid.c:pid_hash[].

We don't need to hash pid == 0 in pidmap_init().  free_pidmap() is never
called with pid == 0 arg, so it will never be reused.  So it is still possible
to use pid == 0 in any PIDTYPE_xxx namespace from kernel/pid.c's POV.

However with this patch we don't hash pid == 0 for PIDTYPE_PID case.  We still
have have PIDTYPE_PGID/PIDTYPE_SID entries with pid == 0: /sbin/init and
kernel threads which don't call daemonize().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:41 -08:00
Oleg Nesterov
c97d98931a [PATCH] kill SET_LINKS/REMOVE_LINKS
Both SET_LINKS() and SET_LINKS/REMOVE_LINKS() have exactly one caller, and
these callers already check thread_group_leader().

This patch kills theese macros, they mix two different things: setting
process's parent and registering it in init_task.tasks list.  Callers are
updated to do these actions by hand.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:41 -08:00
Oleg Nesterov
9b678ece42 [PATCH] don't use REMOVE_LINKS/SET_LINKS for reparenting
There are places where kernel uses REMOVE_LINKS/SET_LINKS while changing
process's ->parent.  Use add_parent/remove_parent instead, they don't abuse
of global process list.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:41 -08:00
Oleg Nesterov
8fafabd86f [PATCH] remove add_parent()'s parent argument
add_parent(p, parent) is always called with parent == p->parent, and it makes
no sense to do it differently.  This patch removes this argument.

No changes in affected .o files.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:41 -08:00
Oleg Nesterov
d799f03597 [PATCH] choose_new_parent: remove unused arg, sanitize exit_state check
'child_reaper' arg is not used in choose_new_parent().

"->exit_state >= EXIT_ZOMBIE" check is a leftover, was
valid when EXIT_ZOMBIE lived in ->state var.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:40 -08:00
Eric W. Biederman
fef23e7fbb [PATCH] exec: allow init to exec from any thread.
After looking at the problem of init calling exec some more I figured out
an easy way to make the code work.

The actual symptom without out this patch is that all threads will die
except pid == 1, and the thread calling exec.  The thread calling exec will
wait forever for pid == 1 to die.

Since pid == 1 does not install a handler for SIGKILL it will never die.

This modifies the tests for init from current->pid == 1 to the equivalent
current == child_reaper.  And then it causes exec in the ugly case to
modify child_reaper.

The only weird symptom is that you wind up with an init process that
doesn't have the oldest start time on the box.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 18:36:40 -08:00
Ingo Molnar
34f192c652 [PATCH] lightweight robust futexes: compat
32-bit syscall compatibility support.  (This patch also moves all futex
related compat functionality into kernel/futex_compat.c.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Acked-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 08:44:49 -08:00
Ingo Molnar
0771dfefc9 [PATCH] lightweight robust futexes: core
Add the core infrastructure for robust futexes: structure definitions, the new
syscalls and the do_exit() based cleanup mechanism.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Acked-by: Ulrich Drepper <drepper@redhat.com>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 08:44:49 -08:00
Ingo Molnar
70522e121a [PATCH] sem2mutex: tty
Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23 07:38:11 -08:00
Al Viro
afc847b7dd [PATCH] don't do exit_io_context() until we know we won't be doing any IO
testcase:

mount /dev/sdb10 /mnt
touch /mnt/tmp/b
umount /mnt
mount /dev/sdb10 /mnt
rm /mnt/tmp/b </mnt/tmp/b
umount /mnt

and watch blkdev_ioc line in /proc/slabinfo.  Vanilla kernel leaks.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-18 18:33:46 -05:00
Björn Steinbrink
5914811acf [PATCH] kjournald keeps reference to namespace
In daemonize() a new thread gets cleaned up and 'merged' with init_task.
The current fs_struct is handled there, but not the current namespace.

This adds the namespace part.

[ Eric Biederman pointed out the namespace wrappers, and also notes that
  we can't ever count on using our parents namespace because we already
  have called exit_fs(), which is the only way to the namespace from a
  process. ]

Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Acked-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-20 20:27:38 -08:00
Arjan van de Ven
858119e159 [PATCH] Unlinline a bunch of other functions
Remove the "inline" keyword from a bunch of big functions in the kernel with
the goal of shrinking it by 30kb to 40kb

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-14 18:27:06 -08:00
Ingo Molnar
b0a9499c3d [PATCH] sched: add new SCHED_BATCH policy
Add a new SCHED_BATCH (3) scheduling policy: such tasks are presumed
CPU-intensive, and will acquire a constant +5 priority level penalty.  Such
policy is nice for workloads that are non-interactive, but which do not
want to give up their nice levels.  The policy is also useful for workloads
that want a deterministic scheduling policy without interactivity causing
extra preemptions (between that workload's tasks).

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-14 18:25:20 -08:00
Randy.Dunlap
c59ede7b78 [PATCH] move capable() to capability.h
- Move capable() from sched.h to capability.h;

- Use <linux/capability.h> where capable() is used
	(in include/, block/, ipc/, kernel/, a few drivers/,
	mm/, security/, & sound/;
	many more drivers/ to go)

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-11 18:42:13 -08:00
Jesper Juhl
3795e1616f [PATCH] Decrease number of pointer derefs in exit.c
Decrease the number of pointer derefs in kernel/exit.c

Benefits of the patch:
 - Fewer pointer dereferences should make the code slightly faster.
 - Size of generated code is smaller
 - improved readability

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10 08:02:01 -08:00
Thomas Gleixner
2ff678b8da [PATCH] hrtimer: switch itimers to hrtimer
switch itimers to a hrtimers-based implementation

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10 08:01:38 -08:00
Ingo Molnar
de5097c2e7 [PATCH] mutex subsystem, more debugging code
more mutex debugging: check for held locks during memory freeing,
task exit, enable sysrq printouts, etc.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
2006-01-09 15:59:21 -08:00
Oren Laadan
e19f247a3d [PATCH] setpgid: should work for sub-threads
setsid() does not work unless the calling process is a
thread_group_leader().

'man setpgid' does not tell anything about that, so I consider this
behaviour is a bug.

Signed-off-by: Oren Laadan <orenl@cs.columbia.edu>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:14:01 -08:00
Oleg Nesterov
485a6435ab [PATCH] little do_group_exit() cleanup
zap_other_threads() sets SIGNAL_GROUP_EXIT at the very start,
do_group_exit() doesn't need to do it.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:55 -08:00
Ingo Molnar
e56d090310 [PATCH] RCU signal handling
RCU tasklist_lock and RCU signal handling: send signals RCU-read-locked
instead of tasklist_lock read-locked.  This is a scalability improvement on
SMP and a preemption-latency improvement under PREEMPT_RCU.

Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: William Irwin <wli@holomorphy.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:40 -08:00
Al Viro
a1261f5461 [PATCH] m68k: introduce task_thread_info
new helper - task_thread_info(task).  On platforms that have thread_info
allocated separately (i.e.  in default case) it simply returns
task->thread_info.  m68k wants (and for good reasons) to embed its thread_info
into task_struct.  So it will (in later patch) have task_thread_info() of its
own.  For now we just add a macro for generic case and convert existing
instances of its body in core kernel to uses of new macro.  Obviously safe -
all normal architectures get the same preprocessor output they used to get.

Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-13 18:14:13 -08:00
Matt Helsley
9f46080c41 [PATCH] Process Events Connector
This patch adds a connector that reports fork, exec, id change, and exit
events for all processes to userspace.  It replaces the fork_advisor patch
that ELSA is currently using.  Applications that may find these events
useful include accounting/auditing (e.g.  ELSA), system activity monitoring
(e.g.  top), security, and resource management (e.g.  CKRM).

Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:35 -08:00