Commit Graph

158650 Commits

Author SHA1 Message Date
Jack Morgenstein
3b4a8cd51e IB/mlx4: Don't allow userspace open while recovering from catastrophic error
Userspace apps are supposed to release all ib device resources if they
receive a fatal async event (IBV_EVENT_DEVICE_FATAL).  However, the
app has no way of knowing when the device has come back up, except to
repeatedly attempt ibv_open_device() until it succeeds.

However, currently there is no protection against the open succeeding
while the device is in being removed following the fatal event.  In
this case, the open will succeed, but as a result the device waits in
the middle of its removal until the new app releases its resources --
and the new app will not do so, since the open succeeded at a point
following the fatal event generation.

This patch adds an "active" flag to the device. The active flag is set
to false (in the fatal event flow) before the "fatal" event is
generated, so any subsequent ibv_dev_open() call to the device will
fail until the device comes back up, thus preventing the above
deadlock.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:50 -07:00
Arputham Benjamin
f5f5951c74 mlx4_core: Distinguish multiple devices in /proc/interrupts
When the mlx4 driver uses the same name for interrupts for every
device in the system.  This can make it very confusing trying to work
out exactly which device MSI-X interrupts are for.  Change the driver
to add the PCI name of the device to the interrupt name.

Signed-off-by: Arputham Benjamin <abenjamin@sgi.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:50 -07:00
Yevgeny Petrilin
1af92e2a21 mlx4_core: Avoid double free_icms
On the error path of mlx4_init_hca(), mlx4_close_hca() is called,
followed by mlx4_free_icms() and mlx4_UNMAP_FA().  But both those
functions are also called from mlx4_close_hca(), which leads to a
double free.

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:49 -07:00
Roland Dreier
fa0681d212 mlx4_core: Allocate and map sufficient ICM memory for EQ context
The current implementation allocates a single host page for EQ context
memory, which was OK when we only allocated a few EQs.  However, since
we now allocate an EQ for each CPU core, this patch removes the
hard-coded limit (which we exceed with 4 KB pages and 128 byte EQ
context entries with 32 CPUs) and uses the same ICM table code as all
other context tables, which ends up simplifying the code quite a bit
while fixing the problem.

This problem was actually hit in practice on a dual-socket Nehalem box
with 16 real hardware threads and sufficiently odd ACPI tables that it
shows on boot

    SMP: Allowing 32 CPUs, 16 hotplug CPUs

so num_possible_cpus() ends up 32, and mlx4 ends up creating 33 MSI-X
interrupts and 33 EQs.  This mlx4 bug means that mlx4 can't even
initialize at all on this quite mainstream system.

Cc: <stable@kernel.org>
Reported-by: Eli Cohen <eli@mellanox.co.il>
Tested-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:49 -07:00
Roland Dreier
338a8fad27 IB/mlx4: Annotate CQ locking
mlx4_ib_lock_cqs()/mlx4_ib_unlock_cqs() are helper functions that
lock/unlock both CQs attached to a QP in the proper order to avoid
AB-BA deadlocks.  Annotate this so sparse can understand what's going
on (and warn us if we misuse these functions).

Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:49 -07:00
Roland Dreier
ff149b2a16 mlx4_core: Remove unnecessary includes of <linux/init.h>
Lots of mlx4 files with no function annotations included <linux/init.h>
for no reason.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:49 -07:00
Roland Dreier
a01df0fe5e mlx4_core: Use pci_request_regions()
The old code used two calls to pci_request_region() to get the two BARs
for the mlx4 device, for no particularly good reason.  Clean up the code
a little by converting this to a single call to pci_request_regions().

Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:48 -07:00
Roel Kluin
1493ab4083 RDMA/amso1100: Check kmalloc() result in c2_register_device()
dev->ibdev.iwcm allocation may fail, prevent a dereference.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:24 -07:00
Jack Morgenstein
b1b8afb833 IB/uverbs: Return ENOSYS for unimplemented commands (not EINVAL)
Since the original commit 883a99c7 ("[IB] uverbs: Add a mask of device
methods allowed for userspace"), the uverbs core returns EINVAL for
commands not implemented by a specific low-level driver.

This creates a problem that there is no way to tell the difference
between an unimplemented command and an implemented one which is
incorrectly invoked (which also returns EINVAL).

The fix is to have unimplemented commands return ENOSYS.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:24 -07:00
Yossi Etigin
e1d7806df3 IB/core: Fix send multicast group leave retry
Until now, retries were only sent when joining a multicast group. This
patch will adds retries when leaving a multicast group as well.

Signed-off-by: Ron Livne <ronli@voltaire.com>
Signed-off-by: Yossi Etigin <yosefe@voltaire.com>
Acked-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:24 -07:00
Marcin Slusarz
f1aa78b26e IB: Use printk_once() for driver versions
Replace open-coded reimplementations with printk_once().

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:24 -07:00
Tobias Klauser
181c74e87e RDMA/amso1100: Use %pM conversion specifier
Use the %pM conversion specifier to print a MAC address.

Signed-off-by: Tobias Klauser <klto@zhaw.ch>
Acked-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:23 -07:00
Roland Dreier
6276e08a9b IB: Use DEFINE_SPINLOCK() for static spinlocks
Rather than just defining static spinlock_t variables and then
initializing them later in init functions, simply define them with
DEFINE_SPINLOCK() and remove the calls to spin_lock_init().  This cleans
up the source a tad and also shrinks the compiled code; eg on x86-64:

add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-40 (-40)
function                                     old     new   delta
ib_uverbs_init                               336     326     -10
ib_mad_init_module                           147     137     -10
ib_sa_init                                   123     103     -20

Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:23 -07:00
Roland Dreier
60f2b652f5 IB/mad: Check hop count field in directed route MAD to avoid array overflow
The hop count field in a directed route MAD is only allowed to be in the
range 0 to 63 (by spec).  Check that this really is the case to avoid
accessing outside the bounds of the hop array.

Reported-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:24:10 -07:00
Jason Gunthorpe
5e47596bee IPoIB: Check multicast address format
Check that the format of multicast link addresses is correct before
taking them from dev->mc_list to priv->multicast_list.  This way we
never try to send a bogus address to the SA, which prevents badness
from erronous 'ip maddr addr add', broken bonding drivers, etc.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:23:40 -07:00
Roland Dreier
721d67cdca IPoIB: Drop priv->lock before calling ipoib_send()
IPoIB currently must use irqsave locking for priv->lock, since it is
taken from interrupt context in one path.  However, ipoib_send() does
skb_orphan(), and the network stack locking is not IRQ-safe.
Therefore we need to make sure we don't hold priv->lock when calling
ipoib_send() to avoid lockdep warnings (the code was almost certainly
safe in practice, since the only code path that takes priv->lock from
interrupt context would never call into the network stack).

Addresses: http://bugzilla.kernel.org/show_bug.cgi?id=13757
Reported-by: Bart Van Assche <bart.vanassche@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:23:40 -07:00
Roland Dreier
cd0bcf4cb9 IPoIB: Remove unused <rdma/ib_cache.h> includes
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:23:38 -07:00
Roel Kluin
286b63d096 IB/ipath: strncpy() doesn't always NUL-terminate
strlcpy() will always null terminate the string.  node_desc is not
guaranteed to be NUL-terminated so just use memcpy().

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:23:21 -07:00
Joachim Fenkes
6303e74c69 IB/ehca: Fix CQE flags reporting
The driver was reporting CQE flags in the wrong bit positions, causing
consumers to miss incoming immediate data.

Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:22:55 -07:00
Joachim Fenkes
d706834d99 IB/ehca: Construct MAD redirect replies from request MAD
The old code used a lot of hard-coded values, which might not be valid
in all environments (especially routed fabrics or partitioned
subnets).  Copy as much information as possible from the incoming
request to correct that.

Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:22:55 -07:00
Alexander Schmidt
50d40b8e53 IB/ehca: Make port autodetect mode the default
Make port autodetect mode the default for the ehca driver. The
autodetect code has been in the kernel for several releases now and
has proved to be stable.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:22:54 -07:00
Steve Wise
a52bf98d99 RDMA/cxgb3: Wake up any waiters on peer close/abort
A close/abort while waiting for a wr_ack during connection migration
can cause a hung process in iwch_accept_cr/iwch_reject_cr.

The fix is to set rpl_error/rpl_done and wake up the waiters when we
get a close/abort while in MPA_REQ_RCVD state.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:22:38 -07:00
Steve Wise
6e47fe4350 RDMA/cxgb3: Don't free endpoints early
- Keep ref on connection request endpoints until either accepted or
  rejected so it doesn't get freed early.

- Endpoint flags now need to be set via atomic bitops because they can
  be set on both the iw_cxgb3 workqueue thread and user disconnect
  threads.

- Don't move out of CLOSING too early due to multiple calls to
  iwch_ep_disconnect.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:22:38 -07:00
Steve Wise
fa0d4c11c4 RDMA/cxgb3: Handle port events properly
Massage the err_handler upcall into an event handler upcall, pass
netdev port events to the cxgb3 ULPs and generate RDMA port events
based on LLD port events.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:22:38 -07:00
Steve Wise
b496fe82d4 RDMA/cxgb3: Set the appropriate IO channel in rdma_init work requests
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:22:37 -07:00
Steve Wise
3793d2fc3e RDMA/cxgb3: iwch_unregister_device leaks memory
The iwcm struct mem is never freed.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2009-09-05 20:22:36 -07:00
Linus Torvalds
e07cccf404 Linux 2.6.31-rc9 2009-09-05 16:38:12 -07:00
Linus Torvalds
f815c335d2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
  firewire: sbp2: fix freeing of unallocated memory
  firewire: ohci: fix Ricoh R5C832, video reception
  firewire: ohci: fix Agere FW643 and multiple cameras
  firewire: core: fix crash in iso resource management
2009-09-05 14:59:00 -07:00
Roderick Colenbrander
74a01180db powerpc: Fix i8259 interrupt driver kernel crash on ML510
This patch fixes a null pointer exception caused by removal of
'ack()' for level interrupts in the Xilinx interrupt driver.  A recent
change to the xilinx interrupt controller removed the ack hook for
level irqs.

Signed-off-by: Roderick Colenbrander <thunderbird2k@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-05 14:58:07 -07:00
Linus Torvalds
5136a6c0fd Merge git://git.infradead.org/~dwmw2/mtd-2.6.31
* git://git.infradead.org/~dwmw2/mtd-2.6.31:
  JFFS2: add missing verify buffer allocation/deallocation
  mtd: nftl: fix offset alignments
  mtd: nftl: write support is broken
  mtd: m25p80: fix null pointer dereference bug
2009-09-05 14:57:04 -07:00
Linus Torvalds
e505a8d5f9 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: Allow changing max_sectors_kb above the default 512
2009-09-05 14:56:13 -07:00
Linus Torvalds
b71b7dc09a Merge branch 'fix/oxygen' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
* 'fix/oxygen' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  sound: oxygen: handle cards with missing EEPROM
  sound: oxygen: fix MCLK rate for 192 kHz playback
2009-09-05 14:55:30 -07:00
Linus Torvalds
59430c2f43 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  tc: Fix unitialized kernel memory leak
  pkt_sched: Revert tasklet_hrtimer changes.
  net: sk_free() should be allowed right after sk_alloc()
  gianfar: gfar_remove needs to call unregister_netdev()
  ipw2200: firmware DMA loading rework
2009-09-05 14:52:41 -07:00
Linus Torvalds
e9ee3a54a1 Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: skcipher - Fix skcipher_dequeue_givcrypt NULL test
2009-09-05 14:51:45 -07:00
Linus Torvalds
3bb314f01c Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
  [CPUFREQ] Re-enable cpufreq suspend and resume code
2009-09-05 14:51:24 -07:00
Linus Torvalds
535e0c1726 Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
  [IA64] fix csum_ipv6_magic()
  [IA64] Fix warning in dma-mapping.c
2009-09-05 14:50:53 -07:00
Linus Torvalds
0edfa2b1b5 Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs
* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: actually enable the swapext compat handler
2009-09-05 14:25:14 -07:00
Linus Torvalds
5a09adf130 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2:
  nilfs2: fix preempt count underflow in nilfs_btnode_prepare_change_key
2009-09-05 14:24:33 -07:00
Linus Torvalds
931f70350e Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: don't assume existence of cpu0
2009-09-05 14:22:00 -07:00
Linus Torvalds
e305fc5ecd Merge branch 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6
* 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
  slub: Fix kmem_cache_destroy() with SLAB_DESTROY_BY_RCU
2009-09-05 13:57:53 -07:00
Linus Torvalds
154f807e55 Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm
* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm:
  dm snapshot: fix on disk chunk size validation
  dm exception store: split set_chunk_size
  dm snapshot: fix header corruption race on invalidation
  dm snapshot: refactor zero_disk_area to use chunk_io
  dm log: userspace add luid to distinguish between concurrent log instances
  dm raid1: do not allow log_failure variable to unset after being set
  dm log: remove incorrect field from userspace table output
  dm log: fix userspace status output
  dm stripe: expose correct io hints
  dm table: add more context to terse warning messages
  dm table: fix queue_limit checking device iterator
  dm snapshot: implement iterate devices
  dm multipath: fix oops when request based io fails when no paths
2009-09-05 13:51:07 -07:00
Linus Torvalds
9b6a3df372 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
  PCI SR-IOV: correct broken resource alignment calculations
2009-09-05 13:50:46 -07:00
Linus Torvalds
d3acd16cda Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  sparc64: Fix bootup with mcount in some configs.
  sparc64: Kill spurious NMI watchdog triggers by increasing limit to 30 seconds.
2009-09-05 13:49:06 -07:00
Linus Torvalds
93697a3cab Merge branch 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf_counter/powerpc: Fix cache event codes for POWER7
  perf_counter: Fix /0 bug in swcounters
  perf_counters: Increase paranoia level
2009-09-05 13:48:37 -07:00
Linus Torvalds
6399534472 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: atkbd - add Compaq Presario R4000-series repeat quirk
  Input: i8042 - add Acer Aspire 5536 to the nomux list
2009-09-05 13:41:29 -07:00
Nicolas Pitre
9de6886ec6 ext2: fix unbalanced kmap()/kunmap()
In ext2_rename(), dir_page is acquired through ext2_dotdot().  It is
then released through ext2_set_link() but only if old_dir != new_dir.
Failing that, the pkmap reference count is never decremented and the
page remains pinned forever.  Repeat that a couple times with highmem
pages and all pkmap slots get exhausted, and every further kmap() calls
end up stalling on the pkmap_map_wait queue at which point the whole
system comes to a halt.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-05 13:41:08 -07:00
Linus Torvalds
ac7ac9f2b9 Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
  ocfs2: ocfs2_write_begin_nolock() should handle len=0
  ocfs2: invalidate dentry if its dentry_lock isn't initialized.
2009-09-05 13:38:37 -07:00
Linus Torvalds
ac89a9174d pty: don't limit the writes to 'pty_space()' inside 'pty_write()'
The whole write-room thing is something that is up to the _caller_ to
worry about, not the pty layer itself.  The total buffer space will
still be limited by the buffering routines themselves, so there is no
advantage or need in having pty_write() artificially limit the size
somehow.

And what happened was that the caller (the n_tty line discipline, in
this case) may have verified that there is room for 2 bytes to be
written (for NL -> CRNL expansion), and it used to then do those writes
as two single-byte writes.  And if the first byte written (CR) then
caused a new tty buffer to be allocated, pty_space() may have returned
zero when trying to write the second byte (LF), and then incorrectly
failed the write - leading to a lost newline character.

This should finally fix

	http://bugzilla.kernel.org/show_bug.cgi?id=14015

Reported-by: Mikael Pettersson <mikpe@it.uu.se>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-05 13:27:10 -07:00
Linus Torvalds
37f81fa1f6 n_tty: do O_ONLCR translation as a single write
When translating CR to CRNL in the n_tty line discipline, we did it as
two tty_put_char() calls.  Which works, but is stupid, and has caused
problems before too with bad interactions with the write_room() logic.
The generic USB serial driver had that problem, for example.

Now the pty layer had similar issues after being moved to the generic
tty buffering code (in commit d945cb9cce:
"pty: Rework the pty layer to use the normal buffering logic").

So stop doing the silly separate two writes, and do it as a single write
instead.  That's what the n_tty layer already does for the space
expansion of tabs (XTABS), and it means that we'll now always have just
a single write for the CRNL to match the single 'tty_write_room()' test,
which hopefully means that the next time somebody screws up buffering,
it won't cause weeks of debugging.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-05 12:46:07 -07:00
Oleg Nesterov
a2a8474c3f exec: do not sleep in TASK_TRACED under ->cred_guard_mutex
Tom Horsley reports that his debugger hangs when it tries to read
/proc/pid_of_tracee/maps, this happens since

	"mm_for_maps: take ->cred_guard_mutex to fix the race with exec"
	04b836cbf19e885f8366bccb2e4b0474346c02d

commit in 2.6.31.

But the root of the problem lies in the fact that do_execve() path calls
tracehook_report_exec() which can stop if the tracer sets PT_TRACE_EXEC.

The tracee must not sleep in TASK_TRACED holding this mutex.  Even if we
remove ->cred_guard_mutex from mm_for_maps() and proc_pid_attr_write(),
another task doing PTRACE_ATTACH should not hang until it is killed or the
tracee resumes.

With this patch do_execve() does not use ->cred_guard_mutex directly and
we do not hold it throughout, instead:

	- introduce prepare_bprm_creds() helper, it locks the mutex
	  and calls prepare_exec_creds() to initialize bprm->cred.

	- install_exec_creds() drops the mutex after commit_creds(),
	  and thus before tracehook_report_exec()->ptrace_stop().

	  or, if exec fails,

	  free_bprm() drops this mutex when bprm->cred != NULL which
	  indicates install_exec_creds() was not called.

Reported-by: Tom Horsley <tom.horsley@att.net>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-05 11:30:42 -07:00