Commit Graph

2723 Commits

Author SHA1 Message Date
Oleg Nesterov
bb9ef1cb7d tracing: Change apply_subsystem_event_filter() paths to check file->system == dir
filter_free_subsystem_preds(), filter_free_subsystem_filters() and
replace_system_preds() can simply check file->system->subsystem and
avoid strcmp(call->class->system).

Better yet, we can pass "struct ftrace_subsystem_dir *dir" instead of
event_subsystem and just check file->system == dir.

Thanks to Namhyung Kim who pointed out that replace_system_preds() can
be changed too.

Link: http://lkml.kernel.org/p/20140715184829.GA20516@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-16 14:33:35 -04:00
Oleg Nesterov
ede392a750 tracing/uprobes: Kill the dead TRACE_EVENT_FL_USE_CALL_FILTER logic
alloc_trace_uprobe() sets TRACE_EVENT_FL_USE_CALL_FILTER for unknown
reason and this is simply wrong. Fortunately this has no effect because
register_uprobe_event() clears call->flags after that.

Kill both. This trace_uprobe was kzalloc'ed and we rely on this fact
anyway.

Link: http://lkml.kernel.org/p/20140715184824.GA20505@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-16 14:25:19 -04:00
Oleg Nesterov
b5d09db5ac tracing: Kill call_filter_disable()
It seems that the only purpose of call_filter_disable() is to
make filter_disable() less clear and symmetrical, remove it.

Link: http://lkml.kernel.org/p/20140715184821.GA20498@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-16 14:23:12 -04:00
Oleg Nesterov
57375747b6 tracing: Kill destroy_call_preds()
Remove destroy_call_preds(). Its only caller, __trace_remove_event_call(),
can use free_event_filter() and nullify ->filter by hand.

Perhaps we could keep this trivial helper although imo it is pointless, but
then it should be static in trace_events.c.

Link: http://lkml.kernel.org/p/20140715184816.GA20495@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-16 14:22:32 -04:00
Oleg Nesterov
3e5454d656 tracing: Kill destroy_preds() and destroy_file_preds()
destroy_preds() makes no sense.

The only caller, event_remove(), actually wants destroy_file_preds().
__trace_remove_event_call() does destroy_call_preds() which takes care
of call->filter.

And after the previous change we can simply remove destroy_preds() from
event_remove(), we are going to call remove_event_from_tracers() which
in turn calls remove_event_file_dir()->free_event_filter().

Link: http://lkml.kernel.org/p/20140715184813.GA20488@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-16 14:19:55 -04:00
Steven Rostedt (Red Hat)
646d7043ad ftrace: Allow archs to specify if they need a separate function graph trampoline
Currently if an arch supports function graph tracing, the core code will
just assign the function graph trampoline to the function graph addr that
gets called.

But as the old method for function graph tracing always calls the function
trampoline first and that calls the function graph trampoline, some
archs may have the function graph trampoline dependent on operations that
were done in the function trampoline. This causes function graph tracer
to break on those archs.

Instead of having the default be to set the function graph ftrace_ops
to the function graph trampoline, have it instead just set it to zero
which will keep it from jumping to a trampoline that is not set up
to be jumped directly too.

Link: http://lkml.kernel.org/r/53BED155.9040607@nvidia.com

Reported-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
Tested-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-16 11:01:24 -04:00
Martin Lau
97b8ee8453 ring-buffer: Fix polling on trace_pipe
ring_buffer_poll_wait() should always put the poll_table to its wait_queue
even there is immediate data available.  Otherwise, the following epoll and
read sequence will eventually hang forever:

1. Put some data to make the trace_pipe ring_buffer read ready first
2. epoll_ctl(efd, EPOLL_CTL_ADD, trace_pipe_fd, ee)
3. epoll_wait()
4. read(trace_pipe_fd) till EAGAIN
5. Add some more data to the trace_pipe ring_buffer
6. epoll_wait() -> this epoll_wait() will block forever

~ During the epoll_ctl(efd, EPOLL_CTL_ADD,...) call in step 2,
  ring_buffer_poll_wait() returns immediately without adding poll_table,
  which has poll_table->_qproc pointing to ep_poll_callback(), to its
  wait_queue.
~ During the epoll_wait() call in step 3 and step 6,
  ring_buffer_poll_wait() cannot add ep_poll_callback() to its wait_queue
  because the poll_table->_qproc is NULL and it is how epoll works.
~ When there is new data available in step 6, ring_buffer does not know
  it has to call ep_poll_callback() because it is not in its wait queue.
  Hence, block forever.

Other poll implementation seems to call poll_wait() unconditionally as the very
first thing to do.  For example, tcp_poll() in tcp.c.

Link: http://lkml.kernel.org/p/20140610060637.GA14045@devbig242.prn2.facebook.com

Cc: stable@vger.kernel.org # 2.6.27
Fixes: 2a2cc8f7c4 "ftrace: allow the event pipe to be polled"
Reviewed-by: Chris Mason <clm@fb.com>
Signed-off-by: Martin Lau <kafai@fb.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-15 17:07:47 -04:00
zhangwei(Jovi)
f0160a5a29 tracing: Add TRACE_ITER_PRINTK flag check in __trace_puts/__trace_bputs
The TRACE_ITER_PRINTK check in __trace_puts/__trace_bputs is missing,
so add it, to be consistent with __trace_printk/__trace_bprintk.
Those functions are all called by the same function: trace_printk().

Link: http://lkml.kernel.org/p/51E7A7D6.8090900@huawei.com

Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-15 11:58:40 -04:00
Steven Rostedt (Red Hat)
5f8bf2d263 tracing: Fix graph tracer with stack tracer on other archs
Running my ftrace tests on PowerPC, it failed the test that checks
if function_graph tracer is affected by the stack tracer. It was.
Looking into this, I found that the update_function_graph_func()
must be called even if the trampoline function is not changed.
This is because archs like PowerPC do not support ftrace_ops being
passed by assembly and instead uses a helper function (what the
trampoline function points to). Since this function is not changed
even when multiple ftrace_ops are added to the code, the test that
falls out before calling update_function_graph_func() will miss that
the update must still be done.

Call update_function_graph_function() for all calls to
update_ftrace_function()

Cc: stable@vger.kernel.org # 3.3+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-15 11:10:25 -04:00
zhangwei(Jovi)
8abfb8727f tracing: Add ftrace_trace_stack into __trace_puts/__trace_bputs
Currently trace option stacktrace is not applicable for
trace_printk with constant string argument, the reason is
in __trace_puts/__trace_bputs ftrace_trace_stack is missing.

In contrast, when using trace_printk with non constant string
argument(will call into __trace_printk/__trace_bprintk), then
trace option stacktrace is workable, this inconstant result
will confuses users a lot.

Link: http://lkml.kernel.org/p/51E7A7C9.9040401@huawei.com

Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-15 11:04:40 -04:00
Oleg Nesterov
2448e3493c tracing: instance_rmdir() leaks ftrace_event_file->filter
instance_rmdir() path destroys the event files but forgets to free
file->filter. Change remove_event_file_dir() to free_event_filter().

Link: http://lkml.kernel.org/p/20140711190638.GA19517@redhat.com

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: "zhangwei(Jovi)" <jovi.zhangwei@huawei.com>
Cc: stable@vger.kernel.org # 3.11+
Fixes: f6a84bdc75 "tracing: Introduce remove_event_file_dir()"
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-14 14:41:13 -04:00
Steven Rostedt (Red Hat)
ca65ef1ab6 Merge branch 'trace/ftrace/urgent' into trace/ftrace/core
Needed 099ed15167 "tracing: Remove ftrace_stop/start() from
 reading the trace file" for the removal of ftrace_start/stop().
2014-07-09 11:02:34 -04:00
Steven Rostedt (Red Hat)
099ed15167 tracing: Remove ftrace_stop/start() from reading the trace file
Disabling reading and writing to the trace file should not be able to
disable all function tracing callbacks. There's other users today
(like kprobes and perf). Reading a trace file should not stop those
from happening.

Cc: stable@vger.kernel.org # 3.0+
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 12:45:54 -04:00
Namhyung Kim
d048a8c7b5 tracing: Add description of set_graph_notrace to tracing/README
It was missing the description of set_graph_notrace file.  Add it.

Link: http://lkml.kernel.org/p/1402590233-22321-5-git-send-email-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:45 -04:00
Namhyung Kim
8c006cf7a2 tracing: Improve message of empty set_ftrace_notrace file
When there's no entry in set_ftrace_notrace, it'll print nothing, but
it's better to print something like below like set_graph_notrace does:

  #### no functions disabled ####

Link: http://lkml.kernel.org/p/1402644246-4649-1-git-send-email-namhyung@kernel.org

Reported-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:44 -04:00
Namhyung Kim
280d1429b6 tracing: Improve message of empty set_graph_notrace file
When there's no entry in set_graph_notrace, it'll print below message

  #### all functions enabled ####

While this is technically correct, it's better to print like below:

  #### no functions disabled ####

Link: http://lkml.kernel.org/p/1402590233-22321-3-git-send-email-namhyung@kernel.org

Reported-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:44 -04:00
Namhyung Kim
0d7d9a16ce tracing: Add ftrace_graph_notrace boot parameter
The ftrace_graph_notrace option is for specifying notrace filter for
function graph tracer at boot time.  It can be altered after boot
using set_graph_notrace file on the debugfs.

Link: http://lkml.kernel.org/p/1402590233-22321-2-git-send-email-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:43 -04:00
Fabian Frederick
3448bac329 tracing: Convert pr_warning() to pr_warn() in trace_events.c
Convert pr_warning to standard pr_warn
Define pr_fmt(fmt) fmt to avoid any future default fmt definition

Link: http://lkml.kernel.org/p/1402141388-21144-1-git-send-email-fabf@skynet.be

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:42 -04:00
Namhyung Kim
ef2fbe16ac ftrace: Do not copy hash if O_TRUNC is set
When a filter file is open for writing and O_TRUNC is set, there's no
need to copy and free the filter entries.

Link: http://lkml.kernel.org/p/1402474014-28655-2-git-send-email-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:41 -04:00
Namhyung Kim
1f61be007e ftrace: Fix memory leak on failure path in ftrace_allocate_pages()
As struct ftrace_page is managed in a single linked list, it should
free from the start page.

Link: http://lkml.kernel.org/p/1402474014-28655-1-git-send-email-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:40 -04:00
Namhyung Kim
a737e6dd7b ftrace: Get rid of obsolete global_start_up variable
It seems like it's a leftover from commit 4104d326b6 ("ftrace:
Remove global function list and call function directly").  As it
isn't updated at all, checking its value is meaningless.

Let's get rid of it.

Link: http://lkml.kernel.org/p/1402584972-17824-1-git-send-email-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:40 -04:00
Steven Rostedt (Red Hat)
7b039cb4c5 tracing: Add trace_seq_buffer_ptr() helper function
There's several locations in the kernel that open code the calculation
of the next location in the trace_seq buffer. This is usually done with

  p->buffer + p->len

Instead of having this open coded, supply a helper function in the
header to do it for them. This function is called trace_seq_buffer_ptr().

Link: http://lkml.kernel.org/p/20140626220129.452783019@goodmis.org

Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:39 -04:00
Fabian Frederick
3f4d8f78a0 tracing: Remove unnecessary null test before debugfs_remove()
This fixes checkpatch warning:

"WARNING: debugfs_remove(NULL) is safe this check is probably not required"
Link: http://lkml.kernel.org/p/1403802871-8599-1-git-send-email-fabf@skynet.be

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:38 -04:00
Steven Rostedt (Red Hat)
9096032fbc tracing: Remove trace_seq_reserve()
trace_seq_reserve() has no users in the kernel, it just wastes space.
Remove it.

Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:37 -04:00
Steven Rostedt (Red Hat)
6d2289f3fa tracing: Make trace_seq_putmem_hex() more robust
Currently trace_seq_putmem_hex() can only take as a parameter a pointer
to something that is 8 bytes or less, otherwise it will overflow the
buffer. This is protected by a macro that encompasses the call to
trace_seq_putmem_hex() that has a BUILD_BUG_ON() for the variable before
it is passed in. This is not very robust and if trace_seq_putmem_hex() ever
gets used outside that macro it will cause issues.

Instead of only being able to produce a hex output of memory that is for
a single word, change it to be more robust and allow any size input.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:37 -04:00
Steven Rostedt (Red Hat)
36aabfff50 tracing: Clean up trace_seq.c
For using trace_seq_*() functions in NMI context, I posted a patch to move
it to the lib/ directory. This caused Andrew Morton to take a look at the code.
He went through and gave a lot of comments about missing kernel doc,
inconsistent types for the save variable, mix match of EXPORT_SYMBOL_GPL()
and EXPORT_SYMBOL() as well as missing EXPORT_SYMBOL*()s. There were
a few comments about the way variables were being compared (int vs uint).

All these were good review comments and should be implemented regardless of
if trace_seq.c should be moved to lib/ or not.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:36 -04:00
Steven Rostedt (Red Hat)
12306276fa tracing: Move the trace_seq_* functions into its own trace_seq.c file
The trace_seq_*() functions are a nice utility that allows users to manipulate
buffers with printf() like formats. It has its own trace_seq.h header in
include/linux and should be in its own file. Being tied with trace_output.c
is rather awkward.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:35 -04:00
Masami Hiramatsu
5c27c775d5 ftrace: Simplify ftrace_hash_disable/enable path in ftrace_hash_move
Simplify ftrace_hash_disable/enable path in ftrace_hash_move
for hardening the process if the memory allocation failed.

Link: http://lkml.kernel.org/p/20140617110442.15167.81076.stgit@kbuild-fedora.novalocal

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:34 -04:00
Steven Rostedt (Red Hat)
9674b2fada ftrace: Add trampolines to enabled_functions debug file
The enabled_functions is used to help debug the dynamic function tracing.
Adding what trampolines are attached to files is useful for debugging.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:32 -04:00
Steven Rostedt (Red Hat)
79922b8009 ftrace: Optimize function graph to be called directly
Function graph tracing is a bit different than the function tracers, as
it is processed after either the ftrace_caller or ftrace_regs_caller
and we only have one place to modify the jump to ftrace_graph_caller,
the jump needs to happen after the restore of registeres.

The function graph tracer is dependent on the function tracer, where
even if the function graph tracing is going on by itself, the save and
restore of registers is still done for function tracing regardless of
if function tracing is happening, before it calls the function graph
code.

If there's no function tracing happening, it is possible to just call
the function graph tracer directly, and avoid the wasted effort to save
and restore regs for function tracing.

This requires adding new flags to the dyn_ftrace records:

  FTRACE_FL_TRAMP
  FTRACE_FL_TRAMP_EN

The first is set if the count for the record is one, and the ftrace_ops
associated to that record has its own trampoline. That way the mcount code
can call that trampoline directly.

In the future, trampolines can be added to arbitrary ftrace_ops, where you
can have two or more ftrace_ops registered to ftrace (like kprobes and perf)
and if they are not tracing the same functions, then instead of doing a
loop to check all registered ftrace_ops against their hashes, just call the
ftrace_ops trampoline directly, which would call the registered ftrace_ops
function directly.

Without this patch perf showed:

  0.05%  hackbench  [kernel.kallsyms]  [k] ftrace_caller
  0.05%  hackbench  [kernel.kallsyms]  [k] arch_local_irq_save
  0.05%  hackbench  [kernel.kallsyms]  [k] native_sched_clock
  0.04%  hackbench  [kernel.kallsyms]  [k] __buffer_unlock_commit
  0.04%  hackbench  [kernel.kallsyms]  [k] preempt_trace
  0.04%  hackbench  [kernel.kallsyms]  [k] prepare_ftrace_return
  0.04%  hackbench  [kernel.kallsyms]  [k] __this_cpu_preempt_check
  0.04%  hackbench  [kernel.kallsyms]  [k] ftrace_graph_caller

See that the ftrace_caller took up more time than the ftrace_graph_caller
did.

With this patch:

  0.05%  hackbench  [kernel.kallsyms]  [k] __buffer_unlock_commit
  0.04%  hackbench  [kernel.kallsyms]  [k] call_filter_check_discard
  0.04%  hackbench  [kernel.kallsyms]  [k] ftrace_graph_caller
  0.04%  hackbench  [kernel.kallsyms]  [k] sched_clock

The ftrace_caller is no where to be found and ftrace_graph_caller still
takes up the same percentage.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01 07:13:31 -04:00
Oleg Nesterov
fb6bab6a5a tracing/uprobes: Fix the usage of uprobe_buffer_enable() in probe_event_enable()
The usage of uprobe_buffer_enable() added by dcad1a20 is very wrong,

1. uprobe_buffer_enable() and uprobe_buffer_disable() are not balanced,
   _enable() should be called only if !enabled.

2. If uprobe_buffer_enable() fails probe_event_enable() should clear
   tp.flags and free event_file_link.

3. If uprobe_register() fails it should do uprobe_buffer_disable().

Link: http://lkml.kernel.org/p/20140627170146.GA18332@redhat.com

Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Fixes: dcad1a204f "tracing/uprobes: Fetch args before reserving a ring buffer"
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-30 13:22:33 -04:00
Oleg Nesterov
f786106e80 tracing/uprobes: Kill the bogus UPROBE_HANDLER_REMOVE code in uprobe_dispatcher()
I do not know why dd9fa555d7 "tracing/uprobes: Move argument fetching
to uprobe_dispatcher()" added the UPROBE_HANDLER_REMOVE, but it looks
wrong.

OK, perhaps it makes sense to avoid store_trace_args() if the tracee is
nacked by uprobe_perf_filter(). But then we should kill the same code
in uprobe_perf_func() and unify the TRACE/PROFILE filtering (we need to
do this anyway to mix perf/ftrace). Until then this code actually adds
the pessimization because uprobe_perf_filter() will be called twice and
return T in likely case.

Link: http://lkml.kernel.org/p/20140627170143.GA18329@redhat.com

Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-30 13:22:23 -04:00
Oleg Nesterov
4821254206 tracing/uprobes: Revert "Support mix of ftrace and perf"
This reverts commit 43fe98913c.

This patch is very wrong. Firstly, this change leads to unbalanced
uprobe_unregister(). Just for example,

	# perf probe -x /lib/libc.so.6 syscall
	# echo 1 >> /sys/kernel/debug/tracing/events/probe_libc/enable
	# perf record -e probe_libc:syscall whatever

after that uprobe is dead (unregistered) but the user of ftrace/perf
can't know this, and it looks as if nobody hits this probe.

This would be easy to fix, but there are other reasons why it is not
simple to mix ftrace and perf. If nothing else, they can't share the
same ->consumer.filter. This is fixable too, but probably we need to
fix the poorly designed uprobe_register() interface first. At least
"register" and "apply" should be clearly separated.

Link: http://lkml.kernel.org/p/20140627170136.GA18319@redhat.com

Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: "zhangwei(Jovi)" <jovi.zhangwei@huawei.com>
Cc: stable@vger.kernel.org # v3.14
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-30 13:21:58 -04:00
Steven Rostedt (Red Hat)
0376bde11b ftrace: Add ftrace_rec_counter() macro to simplify the code
The ftrace dynamic record has a flags element that also has a counter.
Instead of hard coding "rec->flags & ~FTRACE_FL_MASK" all over the
place. Use a macro instead.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-30 10:09:56 -04:00
Steven Rostedt (Red Hat)
4fbb48cb11 ftrace: Allow no regs if no more callbacks require it
When registering a function callback for the function tracer, the ops
can specify if it wants to save full regs (like an interrupt would)
for each function that it traces, or if it does not care about regs
and just wants to have the fastest return possible.

Once a ops has registered a function, if other ops register that
function they all will receive the regs too. That's because it does
the work once, it does it for everyone.

Now if the ops wanting regs unregisters the function so that there's
only ops left that do not care about regs, those ops will still
continue getting regs and going through the work for it on that
function. This is because the disabling of the rec counter only
sees the ops registered, and does not see the ops that are still
attached, and does not know if the current ops that are still attached
want regs or not. To play it safe, it just keeps regs being processed
until no function is registered anymore.

Instead of doing that, check the ops that are still registered for that
function and if none want regs for it anymore, then disable the
processing of regs.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-30 10:09:53 -04:00
Linus Torvalds
8841c8b3c4 One bug fix that goes back to 3.10. Accessing a non existent buffer
if "possible cpus" is greater than actual CPUs (including offline CPUs).
 
 Namhyung Kim did some reviews of the patches I sent this merge window and
 found a memory leak and had a few clean ups.
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Merge tag 'trace-3.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing cleanups and bugfixes from Steven Rostedt:
 "One bug fix that goes back to 3.10.  Accessing a non existent buffer
  if "possible cpus" is greater than actual CPUs (including offline
  CPUs).

  Namhyung Kim did some reviews of the patches I sent this merge window
  and found a memory leak and had a few clean ups"

* tag 'trace-3.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix check of ftrace_trace_arrays list_empty() check
  tracing: Fix leak of per cpu max data in instances
  tracing: Cleanup saved_cmdlines_size changes
  ring-buffer: Check if buffer exists before polling
2014-06-12 21:07:25 -07:00
Linus Torvalds
3737a12761 Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull more perf updates from Ingo Molnar:
 "A second round of perf updates:

   - wide reaching kprobes sanitization and robustization, with the hope
     of fixing all 'probe this function crashes the kernel' bugs, by
     Masami Hiramatsu.

   - uprobes updates from Oleg Nesterov: tmpfs support, corner case
     fixes and robustization work.

   - perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo
     et al:
        * Add support to accumulate hist periods (Namhyung Kim)
        * various fixes, refactorings and enhancements"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
  perf: Differentiate exec() and non-exec() comm events
  perf: Fix perf_event_comm() vs. exec() assumption
  uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates
  perf/documentation: Add description for conditional branch filter
  perf/x86: Add conditional branch filtering support
  perf/tool: Add conditional branch filter 'cond' to perf record
  perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND'
  uprobes: Teach copy_insn() to support tmpfs
  uprobes: Shift ->readpage check from __copy_insn() to uprobe_register()
  perf/x86: Use common PMU interrupt disabled code
  perf/ARM: Use common PMU interrupt disabled code
  perf: Disable sampled events if no PMU interrupt
  perf: Fix use after free in perf_remove_from_context()
  perf tools: Fix 'make help' message error
  perf record: Fix poll return value propagation
  perf tools: Move elide bool into perf_hpp_fmt struct
  perf tools: Remove elide setup for SORT_MODE__MEMORY mode
  perf tools: Fix "==" into "=" in ui_browser__warning assignment
  perf tools: Allow overriding sysfs and proc finding with env var
  perf tools: Consider header files outside perf directory in tags target
  ...
2014-06-12 19:18:49 -07:00
Steven Rostedt (Red Hat)
da9c3413a2 tracing: Fix check of ftrace_trace_arrays list_empty() check
The check that tests if ftrace_trace_arrays is empty in
top_trace_array(), uses the .prev pointer:

  if (list_empty(ftrace_trace_arrays.prev))

instead of testing the variable itself:

  if (list_empty(&ftrace_trace_arrays))

Although it is technically correct, it is awkward and confusing.
Use the proper method.

Link: http://lkml.kernel.org/r/87oay1bas8.fsf@sejong.aot.lge.com

Reported-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-10 13:53:50 -04:00
Steven Rostedt (Red Hat)
f0b70cc48c tracing: Fix leak of per cpu max data in instances
The freeing of an instance, if max data is configured, there will be
per cpu data structures created. But these are not freed when the instance
is deleted, which causes a memory leak.

A new helper function is added that frees the individual buffers within a
trace array, instead of duplicating the code. This way changes made for one
are applied to the other (normal buffer vs max buffer).

Link: http://lkml.kernel.org/r/87k38pbake.fsf@sejong.aot.lge.com

Reported-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-10 12:06:30 -04:00
Namhyung Kim
a6af8fbf17 tracing: Cleanup saved_cmdlines_size changes
The recent addition of saved_cmdlines_size file had some remaining
(minor - mostly coding style) issues.  Fix them by passing pointer
name to sizeof() and using scnprintf().

Link: http://lkml.kernel.org/p/1402384295-23680-1-git-send-email-namhyung@kernel.org

Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-10 09:51:10 -04:00
Steven Rostedt (Red Hat)
8b8b36834d ring-buffer: Check if buffer exists before polling
The per_cpu buffers are created one per possible CPU. But these do
not mean that those CPUs are online, nor do they even exist.

With the addition of the ring buffer polling, it assumes that the
caller polls on an existing buffer. But this is not the case if
the user reads trace_pipe from a CPU that does not exist, and this
causes the kernel to crash.

Simple fix is to check the cpu against buffer bitmask against to see
if the buffer was allocated or not and return -ENODEV if it is
not.

More updates were done to pass the -ENODEV back up to userspace.

Link: http://lkml.kernel.org/r/5393DB61.6060707@oracle.com

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-10 09:46:00 -04:00
Linus Torvalds
214b931320 Lots of tweaks, small fixes, optimizations, and some helper functions
to help out the rest of the kernel to ease their use of trace events.
 
 The big change for this release is the allowing of other tracers,
 such as the latency tracers, to be used in the trace instances and allow
 for function or function graph tracing to be in the top level
 simultaneously.
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Merge tag 'trace-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "Lots of tweaks, small fixes, optimizations, and some helper functions
  to help out the rest of the kernel to ease their use of trace events.

  The big change for this release is the allowing of other tracers, such
  as the latency tracers, to be used in the trace instances and allow
  for function or function graph tracing to be in the top level
  simultaneously"

* tag 'trace-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
  tracing: Fix memory leak on instance deletion
  tracing: Fix leak of ring buffer data when new instances creation fails
  tracing/kprobes: Avoid self tests if tracing is disabled on boot up
  tracing: Return error if ftrace_trace_arrays list is empty
  tracing: Only calculate stats of tracepoint benchmarks for 2^32 times
  tracing: Convert stddev into u64 in tracepoint benchmark
  tracing: Introduce saved_cmdlines_size file
  tracing: Add __get_dynamic_array_len() macro for trace events
  tracing: Remove unused variable in trace_benchmark
  tracing: Eliminate double free on failure of allocation on boot up
  ftrace/x86: Call text_ip_addr() instead of the duplicated code
  tracing: Print max callstack on stacktrace bug
  tracing: Move locking of trace_cmdline_lock into start/stop seq calls
  tracing: Try again for saved cmdline if failed due to locking
  tracing: Have saved_cmdlines use the seq_read infrastructure
  tracing: Add tracepoint benchmark tracepoint
  tracing: Print nasty banner when trace_printk() is in use
  tracing: Add funcgraph_tail option to print function name after closing braces
  tracing: Eliminate duplicate TRACE_GRAPH_PRINT_xx defines
  tracing: Add __bitmask() macro to trace events to cpumasks and other bitmasks
  ...
2014-06-09 16:39:15 -07:00
Steven Rostedt (Red Hat)
a9fcaaac37 tracing: Fix memory leak on instance deletion
When an instance is created, it also gets a snapshot ring buffer
allocated (with minimum of pages). But when it is deleted the snapshot
buffer is not. There was a helper function added to match the allocation
of these ring buffers to a way to free them, but it wasn't used by
the deletion of an instance. Using that helper function solves this
memory leak.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-06 23:17:28 -04:00
Steven Rostedt (Red Hat)
23aaa3c18e tracing: Fix leak of ring buffer data when new instances creation fails
Yoshihiro Yunomae reported that the ring buffer data for a trace
instance does not get properly cleaned up when it fails. He proposed
a patch that manually cleaned the data up and addad a bunch of labels.
The labels are not needed because all trace array is allocated with
a kzalloc which initializes it to 0 and all kfree()s can take a NULL
pointer and will ignore it.

Adding a new helper function free_trace_buffers() that can also take
null buffers to free the buffers that were allocated by
allocate_trace_buffers().

Link: http://lkml.kernel.org/r/20140605223522.32311.31664.stgit@yunodevel

Reported-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-06 04:53:40 -04:00
Yoshihiro YUNOMAE
748ec3a20e tracing/kprobes: Avoid self tests if tracing is disabled on boot up
If tracing is disabled on boot up, the kernel should not execute tracing
self tests. The kernel should check whether tracing is disabled or not
before executing any of the tracing self tests.

Link: http://lkml.kernel.org/p/20140605223520.32311.56097.stgit@yunodevel

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-06 04:53:39 -04:00
Yoshihiro YUNOMAE
dc81e5e3ab tracing: Return error if ftrace_trace_arrays list is empty
ftrace_trace_arrays links global_trace.list. However, global_trace
is not added to ftrace_trace_arrays if trace_alloc_buffers() failed.
As the result, ftrace_trace_arrays becomes an empty list. If
ftrace_trace_arrays is an empty list, current top_trace_array() returns
an invalid pointer. As the result, the kernel can induce memory corruption
or panic.

Current implementation does not check whether ftrace_trace_arrays is empty
list or not. So, in this patch, if ftrace_trace_arrays is empty list,
top_trace_array() returns NULL. Moreover, this patch makes all functions
calling top_trace_array() handle it appropriately.

Link: http://lkml.kernel.org/p/20140605223517.32311.99233.stgit@yunodevel

Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-06 04:47:46 -04:00
Steven Rostedt (Red Hat)
34839f5a69 tracing: Only calculate stats of tracepoint benchmarks for 2^32 times
When calculating the average and standard deviation, it is required that
the count be less than UINT_MAX, otherwise the do_div() will get
undefined results. After 2^32 counts of data, the average and standard
deviation should pretty much be set anyway.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-06 00:41:38 -04:00
Steven Rostedt (Red Hat)
72e2fe38ea tracing: Convert stddev into u64 in tracepoint benchmark
I've been told that do_div() expects an unsigned 64 bit number, and
is undefined if a signed is used. This gave a warning on the MIPS
build. I'm not sure if a signed 64 bit dividend is really an issue
or not, but the calculation this is used for is standard deviation,
and that isn't going to be negative. We can just convert it to
unsigned and be safe.

Reported-by: David Daney <ddaney.cavm@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-05 20:35:30 -04:00
Yoshihiro YUNOMAE
939c7a4f04 tracing: Introduce saved_cmdlines_size file
Introduce saved_cmdlines_size file for changing the number of saved pid-comms.
saved_cmdlines currently stores 128 command names using SAVED_CMDLINES, but
'no-existing processes' names are often lost in saved_cmdlines when we
read the trace data. So, by introducing saved_cmdlines_size file, we can
now change the 128 command names saved to something much larger if needed.

When we write a value to saved_cmdlines_size, the number of the value will
be stored in pid-comm list:

	# echo 1024 > /sys/kernel/debug/tracing/saved_cmdlines_size

Here, 1024 command names can be stored. The default number is 128 and the maximum
number is PID_MAX_DEFAULT (=32768 if CONFIG_BASE_SMALL is not set). So, if we
want to avoid losing any command names, we need to set 32768 to
saved_cmdlines_size.

We can read the maximum number of the list:

	# cat /sys/kernel/debug/tracing/saved_cmdlines_size
	128

Link: http://lkml.kernel.org/p/20140605012427.22115.16173.stgit@yunodevel

Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-05 12:35:49 -04:00
Ingo Molnar
10b0256496 Merge branch 'perf/kprobes' into perf/core
Conflicts:
	arch/x86/kernel/traps.c

The kprobes enhancements are fully cooked, ship them upstream.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05 12:26:50 +02:00
Ingo Molnar
c56d34064b Merge branch 'perf/uprobes' into perf/core
These bits from Oleg are fully cooked, ship them to Linus.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05 12:26:27 +02:00
Steven Rostedt (Red Hat)
195d280201 tracing: Remove unused variable in trace_benchmark
Somehow this unused variable warning sneaked past my warnings check
(probably due to it depending on a new config).

kernel/trace/trace_benchmark.c: In function 'trace_do_benchmark':
kernel/trace/trace_benchmark.c:38:6: warning: unused variable 'seedsq' [-Wunused-variable]
  u64 seedsq;
      ^

Link: http://lkml.kernel.org/r/20140604160921.4f4e69c4@canb.auug.org.au

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-04 13:36:29 -04:00
Yoshihiro YUNOMAE
198376cd88 tracing: Eliminate double free on failure of allocation on boot up
If allocation of the max_buffer fails on boot up, the error path will
free both per_cpu data structures from the buffers. With the new redesign
of the code, those structures are freed if allocations failed. That is,
the helper function that allocates the buffers will free the per cpu data
on failure. No need to do it again. In fact, the second free will cause
a bug as the code can not handle a double free.

Link: http://lkml.kernel.org/p/20140603042803.27308.30956.stgit@yunodevel

Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-03 19:58:31 -04:00
Minchan Kim
e317218194 tracing: Print max callstack on stacktrace bug
While I played with my own feature(ex, something on the way to reclaim),
the kernel would easily oops. I guessed that the reason had to do with
stack overflow and wanted to prove it.

I discovered the stack tracer which proved to be very useful for me but
the kernel would oops before my user program gather the information via
"watch cat /sys/kernel/debug/tracing/stack_trace" so I couldn't get any
message from that. What I needed was to have the stack tracer emit the
kernel stack usage before it does the oops so I could find what was
hogging the stack.

This patch shows the callstack of max stack usage right before an oops so
we can find a culprit.

So, the result is as follows.

[ 1116.522206] init: lightdm main process (1246) terminated with status 1
[ 1119.922916] init: failsafe-x main process (1272) terminated with status 1
[ 3887.728131] kworker/u24:1 (6637) used greatest stack depth: 256 bytes left
[ 6397.629227] cc1 (9554) used greatest stack depth: 128 bytes left
[ 7174.467392]         Depth    Size   Location    (47 entries)
[ 7174.467392]         -----    ----   --------
[ 7174.467785]   0)     7248     256   get_page_from_freelist+0xa7/0x920
[ 7174.468506]   1)     6992     352   __alloc_pages_nodemask+0x1cd/0xb20
[ 7174.469224]   2)     6640       8   alloc_pages_current+0x10f/0x1f0
[ 7174.469413]   3)     6632     168   new_slab+0x2c5/0x370
[ 7174.469413]   4)     6464       8   __slab_alloc+0x3a9/0x501
[ 7174.469413]   5)     6456      80   __kmalloc+0x1cb/0x200
[ 7174.469413]   6)     6376     376   vring_add_indirect+0x36/0x200
[ 7174.469413]   7)     6000     144   virtqueue_add_sgs+0x2e2/0x320
[ 7174.469413]   8)     5856     288   __virtblk_add_req+0xda/0x1b0
[ 7174.469413]   9)     5568      96   virtio_queue_rq+0xd3/0x1d0
[ 7174.469413]  10)     5472     128   __blk_mq_run_hw_queue+0x1ef/0x440
[ 7174.469413]  11)     5344      16   blk_mq_run_hw_queue+0x35/0x40
[ 7174.469413]  12)     5328      96   blk_mq_insert_requests+0xdb/0x160
[ 7174.469413]  13)     5232     112   blk_mq_flush_plug_list+0x12b/0x140
[ 7174.469413]  14)     5120     112   blk_flush_plug_list+0xc7/0x220
[ 7174.469413]  15)     5008      64   io_schedule_timeout+0x88/0x100
[ 7174.469413]  16)     4944     128   mempool_alloc+0x145/0x170
[ 7174.469413]  17)     4816      96   bio_alloc_bioset+0x10b/0x1d0
[ 7174.469413]  18)     4720      48   get_swap_bio+0x30/0x90
[ 7174.469413]  19)     4672     160   __swap_writepage+0x150/0x230
[ 7174.469413]  20)     4512      32   swap_writepage+0x42/0x90
[ 7174.469413]  21)     4480     320   shrink_page_list+0x676/0xa80
[ 7174.469413]  22)     4160     208   shrink_inactive_list+0x262/0x4e0
[ 7174.469413]  23)     3952     304   shrink_lruvec+0x3e1/0x6a0
[ 7174.469413]  24)     3648      80   shrink_zone+0x3f/0x110
[ 7174.469413]  25)     3568     128   do_try_to_free_pages+0x156/0x4c0
[ 7174.469413]  26)     3440     208   try_to_free_pages+0xf7/0x1e0
[ 7174.469413]  27)     3232     352   __alloc_pages_nodemask+0x783/0xb20
[ 7174.469413]  28)     2880       8   alloc_pages_current+0x10f/0x1f0
[ 7174.469413]  29)     2872     200   __page_cache_alloc+0x13f/0x160
[ 7174.469413]  30)     2672      80   find_or_create_page+0x4c/0xb0
[ 7174.469413]  31)     2592      80   ext4_mb_load_buddy+0x1e9/0x370
[ 7174.469413]  32)     2512     176   ext4_mb_regular_allocator+0x1b7/0x460
[ 7174.469413]  33)     2336     128   ext4_mb_new_blocks+0x458/0x5f0
[ 7174.469413]  34)     2208     256   ext4_ext_map_blocks+0x70b/0x1010
[ 7174.469413]  35)     1952     160   ext4_map_blocks+0x325/0x530
[ 7174.469413]  36)     1792     384   ext4_writepages+0x6d1/0xce0
[ 7174.469413]  37)     1408      16   do_writepages+0x23/0x40
[ 7174.469413]  38)     1392      96   __writeback_single_inode+0x45/0x2e0
[ 7174.469413]  39)     1296     176   writeback_sb_inodes+0x2ad/0x500
[ 7174.469413]  40)     1120      80   __writeback_inodes_wb+0x9e/0xd0
[ 7174.469413]  41)     1040     160   wb_writeback+0x29b/0x350
[ 7174.469413]  42)      880     208   bdi_writeback_workfn+0x11c/0x480
[ 7174.469413]  43)      672     144   process_one_work+0x1d2/0x570
[ 7174.469413]  44)      528     112   worker_thread+0x116/0x370
[ 7174.469413]  45)      416     240   kthread+0xf3/0x110
[ 7174.469413]  46)      176     176   ret_from_fork+0x7c/0xb0
[ 7174.469413] ------------[ cut here ]------------
[ 7174.469413] kernel BUG at kernel/trace/trace_stack.c:174!
[ 7174.469413] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 7174.469413] Dumping ftrace buffer:
[ 7174.469413]    (ftrace buffer empty)
[ 7174.469413] Modules linked in:
[ 7174.469413] CPU: 0 PID: 440 Comm: kworker/u24:0 Not tainted 3.14.0+ #212
[ 7174.469413] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 7174.469413] Workqueue: writeback bdi_writeback_workfn (flush-253:0)
[ 7174.469413] task: ffff880034170000 ti: ffff880029518000 task.ti: ffff880029518000
[ 7174.469413] RIP: 0010:[<ffffffff8112336e>]  [<ffffffff8112336e>] stack_trace_call+0x2de/0x340
[ 7174.469413] RSP: 0000:ffff880029518290  EFLAGS: 00010046
[ 7174.469413] RAX: 0000000000000030 RBX: 000000000000002f RCX: 0000000000000000
[ 7174.469413] RDX: 0000000000000000 RSI: 000000000000002f RDI: ffffffff810b7159
[ 7174.469413] RBP: ffff8800295182f0 R08: ffffffffffffffff R09: 0000000000000000
[ 7174.469413] R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff82768dfc
[ 7174.469413] R13: 000000000000f2e8 R14: ffff8800295182b8 R15: 00000000000000f8
[ 7174.469413] FS:  0000000000000000(0000) GS:ffff880037c00000(0000) knlGS:0000000000000000
[ 7174.469413] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 7174.469413] CR2: 00002acd0b994000 CR3: 0000000001c0b000 CR4: 00000000000006f0
[ 7174.469413] Stack:
[ 7174.469413]  0000000000000000 ffffffff8114fdb7 0000000000000087 0000000000001c50
[ 7174.469413]  0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 7174.469413]  0000000000000002 ffff880034170000 ffff880034171028 0000000000000000
[ 7174.469413] Call Trace:
[ 7174.469413]  [<ffffffff8114fdb7>] ? get_page_from_freelist+0xa7/0x920
[ 7174.469413]  [<ffffffff816eee3f>] ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff81165065>] ? next_zones_zonelist+0x5/0x70
[ 7174.469413]  [<ffffffff810a23fa>] ? __bfs+0x11a/0x270
[ 7174.469413]  [<ffffffff81165065>] ? next_zones_zonelist+0x5/0x70
[ 7174.469413]  [<ffffffff8114fdb7>] ? get_page_from_freelist+0xa7/0x920
[ 7174.469413]  [<ffffffff8119092f>] ? alloc_pages_current+0x10f/0x1f0
[ 7174.469413]  [<ffffffff811507fd>] __alloc_pages_nodemask+0x1cd/0xb20
[ 7174.469413]  [<ffffffff810a4de6>] ? check_irq_usage+0x96/0xe0
[ 7174.469413]  [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff8119092f>] alloc_pages_current+0x10f/0x1f0
[ 7174.469413]  [<ffffffff81199cd5>] ? new_slab+0x2c5/0x370
[ 7174.469413]  [<ffffffff81199cd5>] new_slab+0x2c5/0x370
[ 7174.469413]  [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff816db002>] __slab_alloc+0x3a9/0x501
[ 7174.469413]  [<ffffffff8119af8b>] ? __kmalloc+0x1cb/0x200
[ 7174.469413]  [<ffffffff8141dc46>] ? vring_add_indirect+0x36/0x200
[ 7174.469413]  [<ffffffff8141dc46>] ? vring_add_indirect+0x36/0x200
[ 7174.469413]  [<ffffffff8141dc46>] ? vring_add_indirect+0x36/0x200
[ 7174.469413]  [<ffffffff8119af8b>] __kmalloc+0x1cb/0x200
[ 7174.469413]  [<ffffffff8141de10>] ? vring_add_indirect+0x200/0x200
[ 7174.469413]  [<ffffffff8141dc46>] vring_add_indirect+0x36/0x200
[ 7174.469413]  [<ffffffff8141e402>] virtqueue_add_sgs+0x2e2/0x320
[ 7174.469413]  [<ffffffff8148e35a>] __virtblk_add_req+0xda/0x1b0
[ 7174.469413]  [<ffffffff8148e503>] virtio_queue_rq+0xd3/0x1d0
[ 7174.469413]  [<ffffffff8134aa0f>] __blk_mq_run_hw_queue+0x1ef/0x440
[ 7174.469413]  [<ffffffff8134b0d5>] blk_mq_run_hw_queue+0x35/0x40
[ 7174.469413]  [<ffffffff8134b7bb>] blk_mq_insert_requests+0xdb/0x160
[ 7174.469413]  [<ffffffff8134be5b>] blk_mq_flush_plug_list+0x12b/0x140
[ 7174.469413]  [<ffffffff81342237>] blk_flush_plug_list+0xc7/0x220
[ 7174.469413]  [<ffffffff816e60ef>] ? _raw_spin_unlock_irqrestore+0x3f/0x70
[ 7174.469413]  [<ffffffff816e16e8>] io_schedule_timeout+0x88/0x100
[ 7174.469413]  [<ffffffff816e1665>] ? io_schedule_timeout+0x5/0x100
[ 7174.469413]  [<ffffffff81149415>] mempool_alloc+0x145/0x170
[ 7174.469413]  [<ffffffff8109baf0>] ? __init_waitqueue_head+0x60/0x60
[ 7174.469413]  [<ffffffff811e246b>] bio_alloc_bioset+0x10b/0x1d0
[ 7174.469413]  [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0
[ 7174.469413]  [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0
[ 7174.469413]  [<ffffffff81184110>] get_swap_bio+0x30/0x90
[ 7174.469413]  [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0
[ 7174.469413]  [<ffffffff81184660>] __swap_writepage+0x150/0x230
[ 7174.469413]  [<ffffffff810ab405>] ? do_raw_spin_unlock+0x5/0xa0
[ 7174.469413]  [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0
[ 7174.469413]  [<ffffffff81184515>] ? __swap_writepage+0x5/0x230
[ 7174.469413]  [<ffffffff81184782>] swap_writepage+0x42/0x90
[ 7174.469413]  [<ffffffff8115ae96>] shrink_page_list+0x676/0xa80
[ 7174.469413]  [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff8115b872>] shrink_inactive_list+0x262/0x4e0
[ 7174.469413]  [<ffffffff8115c1c1>] shrink_lruvec+0x3e1/0x6a0
[ 7174.469413]  [<ffffffff8115c4bf>] shrink_zone+0x3f/0x110
[ 7174.469413]  [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff8115c9e6>] do_try_to_free_pages+0x156/0x4c0
[ 7174.469413]  [<ffffffff8115cf47>] try_to_free_pages+0xf7/0x1e0
[ 7174.469413]  [<ffffffff81150db3>] __alloc_pages_nodemask+0x783/0xb20
[ 7174.469413]  [<ffffffff8119092f>] alloc_pages_current+0x10f/0x1f0
[ 7174.469413]  [<ffffffff81145c0f>] ? __page_cache_alloc+0x13f/0x160
[ 7174.469413]  [<ffffffff81145c0f>] __page_cache_alloc+0x13f/0x160
[ 7174.469413]  [<ffffffff81146c6c>] find_or_create_page+0x4c/0xb0
[ 7174.469413]  [<ffffffff811463e5>] ? find_get_page+0x5/0x130
[ 7174.469413]  [<ffffffff812837b9>] ext4_mb_load_buddy+0x1e9/0x370
[ 7174.469413]  [<ffffffff81284c07>] ext4_mb_regular_allocator+0x1b7/0x460
[ 7174.469413]  [<ffffffff81281070>] ? ext4_mb_use_preallocated+0x40/0x360
[ 7174.469413]  [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff81287eb8>] ext4_mb_new_blocks+0x458/0x5f0
[ 7174.469413]  [<ffffffff8127d83b>] ext4_ext_map_blocks+0x70b/0x1010
[ 7174.469413]  [<ffffffff8124e6d5>] ext4_map_blocks+0x325/0x530
[ 7174.469413]  [<ffffffff81253871>] ext4_writepages+0x6d1/0xce0
[ 7174.469413]  [<ffffffff812531a0>] ? ext4_journalled_write_end+0x330/0x330
[ 7174.469413]  [<ffffffff811539b3>] do_writepages+0x23/0x40
[ 7174.469413]  [<ffffffff811d2365>] __writeback_single_inode+0x45/0x2e0
[ 7174.469413]  [<ffffffff811d36ed>] writeback_sb_inodes+0x2ad/0x500
[ 7174.469413]  [<ffffffff811d39de>] __writeback_inodes_wb+0x9e/0xd0
[ 7174.469413]  [<ffffffff811d40bb>] wb_writeback+0x29b/0x350
[ 7174.469413]  [<ffffffff81057c3d>] ? __local_bh_enable_ip+0x6d/0xd0
[ 7174.469413]  [<ffffffff811d6e9c>] bdi_writeback_workfn+0x11c/0x480
[ 7174.469413]  [<ffffffff81070610>] ? process_one_work+0x170/0x570
[ 7174.469413]  [<ffffffff81070672>] process_one_work+0x1d2/0x570
[ 7174.469413]  [<ffffffff81070610>] ? process_one_work+0x170/0x570
[ 7174.469413]  [<ffffffff81071bb6>] worker_thread+0x116/0x370
[ 7174.469413]  [<ffffffff81071aa0>] ? manage_workers.isra.19+0x2e0/0x2e0
[ 7174.469413]  [<ffffffff81078e53>] kthread+0xf3/0x110
[ 7174.469413]  [<ffffffff81078d60>] ? flush_kthread_worker+0x150/0x150
[ 7174.469413]  [<ffffffff816ef0ec>] ret_from_fork+0x7c/0xb0
[ 7174.469413]  [<ffffffff81078d60>] ? flush_kthread_worker+0x150/0x150
[ 7174.469413] Code: c0 49 bc fc 8d 76 82 ff ff ff ff e8 44 5a 5b 00 31 f6 8b 05 95 2b b3 00 48 39 c6 7d 0e 4c 8b 04 f5 20 5f c5 81 49 83 f8 ff 75 11 <0f> 0b 48 63 05 71 5a 64 01 48 29 c3 e9 d0 fd ff ff 48 8d 5e 01
[ 7174.469413] RIP  [<ffffffff8112336e>] stack_trace_call+0x2de/0x340
[ 7174.469413]  RSP <ffff880029518290>
[ 7174.469413] ---[ end trace c97d325b36b718f3 ]---

Link: http://lkml.kernel.org/p/1401683592-1651-1-git-send-email-minchan@kernel.org

Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-02 16:43:49 -04:00
Steven Rostedt (Red Hat)
4c27e756bc tracing: Move locking of trace_cmdline_lock into start/stop seq calls
With the conversion of the saved_cmdlines output to use seq_read, there
is now a race between accessing the values of the saved_cmdlines and
the writing to them. The trace_cmdline_lock needs to be taken at
the start and stop of the seq calls.

A new __trace_find_cmdline() call is created to allow for the look up
to happen without taking the lock.

Fixes: 42584c81c5 tracing: Have saved_cmdlines use the seq_read infrastructure
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-30 13:03:40 -04:00
Steven Rostedt (Red Hat)
379cfdac37 tracing: Try again for saved cmdline if failed due to locking
In order to prevent the saved cmdline cache from being filled when
tracing is not active, the comms are only recorded after a trace event
is recorded.

The problem is, a comm can fail to be recorded if the trace_cmdline_lock
is held. That lock is taken via a trylock to allow it to happen from
any context (including NMI). If the lock fails to be taken, the comm
is skipped. No big deal, as we will try again later.

But! Because of the code that was added to only record after an event,
we may not try again later as the recording is made as a oneshot per
event per CPU.

Only disable the recording of the comm if the comm is actually recorded.

Fixes: 7ffbd48d5c "tracing: Cache comms only after an event occurred"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-30 09:42:39 -04:00
Yoshihiro YUNOMAE
42584c81c5 tracing: Have saved_cmdlines use the seq_read infrastructure
Current tracing_saved_cmdlines_read() implementation is naive; It allocates
a large buffer, constructs output data to that buffer for each read
operation, and then copies a portion of the buffer to the user space
buffer. This has several issues such as slow memory allocation, high
CPU usage, and even corruption of the output data.

The seq_read infrastructure is made to handle this type of work.
By converting it to use seq_read() the code becomes smaller, simplified,
as well as correct.

Link: http://lkml.kernel.org/p/20140220084431.3839.51793.stgit@yunodevel

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-29 23:08:07 -04:00
Steven Rostedt (Red Hat)
81dc9f0ef2 tracing: Add tracepoint benchmark tracepoint
In order to help benchmark the time tracepoints take, a new config
option is added called CONFIG_TRACEPOINT_BENCHMARK. When this option
is set a tracepoint is created called "benchmark:benchmark_event".
When the tracepoint is enabled, it kicks off a kernel thread that
goes into an infinite loop (calling cond_sched() to let other tasks
run), and calls the tracepoint. Each iteration will record the time
it took to write to the tracepoint and the next iteration that
data will be passed to the tracepoint itself. That is, the tracepoint
will report the time it took to do the previous tracepoint.
The string written to the tracepoint is a static string of 128 bytes
to keep the time the same. The initial string is simply a write of
"START". The second string records the cold cache time of the first
write which is not added to the rest of the calculations.

As it is a tight loop, it benchmarks as hot cache. That's fine because
we care most about hot paths that are probably in cache already.

An example of the output:

     START
     first=3672 [COLD CACHED]
     last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
     last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
     last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
     last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
     last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
     last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-29 22:49:54 -04:00
Steven Rostedt
2184db46e4 tracing: Print nasty banner when trace_printk() is in use
trace_printk() is used to debug fast paths within the kernel. Places
that gets called in any context (interrupt or NMI) or thousands of
times a second. Something you do not want to do with a printk().

In order to make it completely lockless as it needs a temporary buffer
to handle some of the string formatting, a page is created per cpu for
every context (four per cpu; normal, softirq, irq, NMI).

Since trace_printk() should only be used for debugging purposes,
there's no reason to waste memory on these buffers on a production
system. That means, trace_printk() should never be used unless a
developer is debugging their kernel. There's macro magic to allocate
the buffers if trace_printk() is used anywhere in the kernel.

To help enforce that trace_printk() isn't used outside of development,
when it is used, a nasty banner is displayed on bootup (or when a module
is loaded that uses trace_printk() and the kernel core does not).

Here's the banner:

 **********************************************************
 **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
 **                                                      **
 ** trace_printk() being used. Allocating extra memory.  **
 **                                                      **
 ** This means that this is a DEBUG kernel and it is     **
 ** unsafe for produciton use.                           **
 **                                                      **
 ** If you see this message and you are not debugging    **
 ** the kernel, report this immediately to your vendor!  **
 **                                                      **
 **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
 **********************************************************

That should hopefully keep developers from trying to sneak in a
trace_printk() or two.

Link: http://lkml.kernel.org/p/20140528131440.2283213c@gandalf.local.home

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-29 20:13:59 -04:00
Robert Elliott
607e3a2920 tracing: Add funcgraph_tail option to print function name after closing braces
In the function-graph tracer, add a funcgraph_tail option
to print the function name on all } lines, not just
functions whose first line is no longer in the trace
buffer.

If a function calls other traced functions, its total
time appears on its } line.  This change allows grep
to be used to determine the function for which the
line corresponds.

Update Documentation/trace/ftrace.txt to describe
this new option.

Link: http://lkml.kernel.org/p/20140520221041.8359.6782.stgit@beardog.cce.hp.com

Signed-off-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-20 23:29:32 -04:00
Robert Elliott
ccdb594653 tracing: Eliminate duplicate TRACE_GRAPH_PRINT_xx defines
Eliminate duplicate TRACE_GRAPH_PRINT_xx defines
in trace_functions_graph.c that are already in
trace.h.

Add TRACE_GRAPH_PRINT_IRQS to trace.h, which is
the only one that is missing.

Link: http://lkml.kernel.org/p/20140520221031.8359.24733.stgit@beardog.cce.hp.com

Signed-off-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-20 23:28:34 -04:00
Steven Rostedt (Red Hat)
4449bf927b tracing: Add __bitmask() macro to trace events to cpumasks and other bitmasks
Being able to show a cpumask of events can be useful as some events
may affect only some CPUs. There is no standard way to record the
cpumask and converting it to a string is rather expensive during
the trace as traces happen in hotpaths. It would be better to record
the raw event mask and be able to parse it at print time.

The following macros were added for use with the TRACE_EVENT() macro:

  __bitmask()
  __assign_bitmask()
  __get_bitmask()

To test this, I added this to the sched_migrate_task event, which
looked like this:

TRACE_EVENT(sched_migrate_task,

	TP_PROTO(struct task_struct *p, int dest_cpu, const struct cpumask *cpus),

	TP_ARGS(p, dest_cpu, cpus),

	TP_STRUCT__entry(
		__array(	char,	comm,	TASK_COMM_LEN	)
		__field(	pid_t,	pid			)
		__field(	int,	prio			)
		__field(	int,	orig_cpu		)
		__field(	int,	dest_cpu		)
		__bitmask(	cpumask, num_possible_cpus()	)
	),

	TP_fast_assign(
		memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
		__entry->pid		= p->pid;
		__entry->prio		= p->prio;
		__entry->orig_cpu	= task_cpu(p);
		__entry->dest_cpu	= dest_cpu;
		__assign_bitmask(cpumask, cpumask_bits(cpus), num_possible_cpus());
	),

	TP_printk("comm=%s pid=%d prio=%d orig_cpu=%d dest_cpu=%d cpumask=%s",
		  __entry->comm, __entry->pid, __entry->prio,
		  __entry->orig_cpu, __entry->dest_cpu,
		  __get_bitmask(cpumask))
);

With the output of:

        ksmtuned-3613  [003] d..2   485.220508: sched_migrate_task: comm=ksmtuned pid=3615 prio=120 orig_cpu=3 dest_cpu=2 cpumask=00000000,0000000f
     migration/1-13    [001] d..5   485.221202: sched_migrate_task: comm=ksmtuned pid=3614 prio=120 orig_cpu=1 dest_cpu=0 cpumask=00000000,0000000f
             awk-3615  [002] d.H5   485.221747: sched_migrate_task: comm=rcu_preempt pid=7 prio=120 orig_cpu=0 dest_cpu=1 cpumask=00000000,000000ff
     migration/2-18    [002] d..5   485.222062: sched_migrate_task: comm=ksmtuned pid=3615 prio=120 orig_cpu=2 dest_cpu=3 cpumask=00000000,0000000f

Link: http://lkml.kernel.org/r/1399377998-14870-6-git-send-email-javi.merino@arm.com
Link: http://lkml.kernel.org/r/20140506132238.22e136d1@gandalf.local.home

Suggested-by: Javi Merino <javi.merino@arm.com>
Tested-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-15 11:29:37 -04:00
Steven Rostedt (Red Hat)
f1b2f2bd58 ftrace: Remove FTRACE_UPDATE_MODIFY_CALL_REGS flag
As the decision to what needs to be done (converting a call to the
ftrace_caller to ftrace_caller_regs or to convert from ftrace_caller_regs
to ftrace_caller) can easily be determined from the rec->flags of
FTRACE_FL_REGS and FTRACE_FL_REGS_EN, there's no need to have the
ftrace_check_record() return either a UPDATE_MODIFY_CALL_REGS or a
UPDATE_MODIFY_CALL. Just he latter is enough. This added flag causes
more complexity than is required. Remove it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:30 -04:00
Steven Rostedt (Red Hat)
7c0868e03b ftrace: Use the ftrace_addr helper functions to find the ftrace_addr
With the moving of the functions that determine what the mcount call site
should be replaced with into the generic code, there is a few places
in the generic code that can use them instead of hard coding it as it
does.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:29 -04:00
Steven Rostedt (Red Hat)
7413af1fb7 ftrace: Make get_ftrace_addr() and get_ftrace_addr_old() global
Move and rename get_ftrace_addr() and get_ftrace_addr_old() to
ftrace_get_addr_new() and ftrace_get_addr_curr() respectively.

This moves these two helper functions in the generic code out from
the arch specific code, and renames them to have a better generic
name. This will allow other archs to use them as well as makes it
a bit easier to work on getting separate trampolines for different
functions.

ftrace_get_addr_new() returns the trampoline address that the mcount
call address will be converted to.

ftrace_get_addr_curr() returns the trampoline address of what the
mcount call address currently jumps to.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:29 -04:00
Steven Rostedt (Red Hat)
68f40969f0 ftrace: Always inline ftrace_hash_empty() helper function
The ftrace_hash_empty() function is a simple test:

	return !hash || !hash->count;

But gcc seems to want to make it a call. As this is in an extreme
hot path of the function tracer, there's no reason it needs to be
a call. I only wrote it to be a helper function anyway, otherwise
it would have been inlined manually.

Force gcc to inline it, as it could have also been a macro.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:28 -04:00
Steven Rostedt (Red Hat)
19eab4a472 ftrace: Write in missing comment from a very old commit
Back in 2011 Commit ed926f9b35 "ftrace: Use counters to enable
functions to trace" changed the way ftrace accounts for enabled
and disabled traced functions. There was a comment started as:

	/*
	 *
	 */

But never finished. Well, that's rather useless. I probably forgot
to save the file before committing it. And it passed review from all
this time.

Anyway, better late than never. I updated the comment to express what
is happening in that somewhat complex code.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:27 -04:00
Steven Rostedt (Red Hat)
66209a5bd4 ftrace: Remove boolean of hash_enable and hash_disable
Commit 4104d326b6 "ftrace: Remove global function list and call
function directly" cleaned up the global_ops filtering and made
the code simpler, but it left a variable "hash_enable" that was used
to know if the hash functions should be updated or not. It was
updated if the global_ops did not override them. As the global_ops
are now no different than any other ftrace_ops, the hash always
gets updated and there's no reason to use the hash_enable boolean.

The same goes for hash_disable used in ftrace_shutdown().

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:25 -04:00
Christoph Lameter
bdffd893a0 tracing: Replace __get_cpu_var uses with this_cpu_ptr
Replace uses of &__get_cpu_var for address calculation with this_cpu_ptr.

Link: http://lkml.kernel.org/p/alpine.DEB.2.10.1404291415560.18364@gentwo.org

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-05 22:40:53 -04:00
Steven Rostedt (Red Hat)
561a4fe851 tracing: Use rcu_dereference_sched() for trace event triggers
As trace event triggers are now part of the mainline kernel, I added
my trace event trigger tests to my test suite I run on all my kernels.
Now these tests get run under different config options, and one of
those options is CONFIG_PROVE_RCU, which checks under lockdep that
the rcu locking primitives are being used correctly. This triggered
the following splat:

===============================
[ INFO: suspicious RCU usage. ]
3.15.0-rc2-test+ #11 Not tainted
-------------------------------
kernel/trace/trace_events_trigger.c:80 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
4 locks held by swapper/1/0:
 #0:  ((&(&j_cdbs->work)->timer)){..-...}, at: [<ffffffff8104d2cc>] call_timer_fn+0x5/0x1be
 #1:  (&(&pool->lock)->rlock){-.-...}, at: [<ffffffff81059856>] __queue_work+0x140/0x283
 #2:  (&p->pi_lock){-.-.-.}, at: [<ffffffff8106e961>] try_to_wake_up+0x2e/0x1e8
 #3:  (&rq->lock){-.-.-.}, at: [<ffffffff8106ead3>] try_to_wake_up+0x1a0/0x1e8

stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.15.0-rc2-test+ #11
Hardware name:                  /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006
 0000000000000001 ffff88007e083b98 ffffffff819f53a5 0000000000000006
 ffff88007b0942c0 ffff88007e083bc8 ffffffff81081307 ffff88007ad96d20
 0000000000000000 ffff88007af2d840 ffff88007b2e701c ffff88007e083c18
Call Trace:
 <IRQ>  [<ffffffff819f53a5>] dump_stack+0x4f/0x7c
 [<ffffffff81081307>] lockdep_rcu_suspicious+0x107/0x110
 [<ffffffff810ee51c>] event_triggers_call+0x99/0x108
 [<ffffffff810e8174>] ftrace_event_buffer_commit+0x42/0xa4
 [<ffffffff8106aadc>] ftrace_raw_event_sched_wakeup_template+0x71/0x7c
 [<ffffffff8106bcbf>] ttwu_do_wakeup+0x7f/0xff
 [<ffffffff8106bd9b>] ttwu_do_activate.constprop.126+0x5c/0x61
 [<ffffffff8106eadf>] try_to_wake_up+0x1ac/0x1e8
 [<ffffffff8106eb77>] wake_up_process+0x36/0x3b
 [<ffffffff810575cc>] wake_up_worker+0x24/0x26
 [<ffffffff810578bc>] insert_work+0x5c/0x65
 [<ffffffff81059982>] __queue_work+0x26c/0x283
 [<ffffffff81059999>] ? __queue_work+0x283/0x283
 [<ffffffff810599b7>] delayed_work_timer_fn+0x1e/0x20
 [<ffffffff8104d3a6>] call_timer_fn+0xdf/0x1be^M
 [<ffffffff8104d2cc>] ? call_timer_fn+0x5/0x1be
 [<ffffffff81059999>] ? __queue_work+0x283/0x283
 [<ffffffff8104d823>] run_timer_softirq+0x1a4/0x22f^M
 [<ffffffff8104696d>] __do_softirq+0x17b/0x31b^M
 [<ffffffff81046d03>] irq_exit+0x42/0x97
 [<ffffffff81a08db6>] smp_apic_timer_interrupt+0x37/0x44
 [<ffffffff81a07a2f>] apic_timer_interrupt+0x6f/0x80
 <EOI>  [<ffffffff8100a5d8>] ? default_idle+0x21/0x32
 [<ffffffff8100a5d6>] ? default_idle+0x1f/0x32
 [<ffffffff8100ac10>] arch_cpu_idle+0xf/0x11
 [<ffffffff8107b3a4>] cpu_startup_entry+0x1a3/0x213
 [<ffffffff8102a23c>] start_secondary+0x212/0x219

The cause is that the triggers are protected by rcu_read_lock_sched() but
the data is dereferenced with rcu_dereference() which expects it to
be protected with rcu_read_lock(). The proper reference should be
rcu_dereference_sched().

Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-02 23:12:42 -04:00
Steven Rostedt (Red Hat)
fd06a54990 ftrace: Have function graph tracer use global_ops for filtering
Commit 4104d326b6 "ftrace: Remove global function list and call
function directly" cleaned up the global_ops filtering and made
the code simpler. But it left out function graph filtering which
also depended on that code. The function graph filtering still
needs to use global_ops as the filter otherwise it wont filter
at all.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-01 23:21:16 -04:00
Oleg Nesterov
927d687480 uprobes/tracing: Fix uprobe_perf_open() on uprobe_apply() failure
uprobe_perf_open()->uprobe_apply() can fail, but this error is wrongly
ignored. Change uprobe_perf_open() to do uprobe_perf_close() and return
the error code in this case.

Change uprobe_perf_close() to propogate the error from uprobe_apply()
as well, although it should not fail.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2014-04-30 19:10:42 +02:00
Oleg Nesterov
ce5f36a58f uprobes/tracing: Make uprobe_perf_close() visible to uprobe_perf_open()
Preparation. Move uprobe_perf_close() up before uprobe_perf_open() to
avoid the forward declaration in the next patch and make it readable.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2014-04-30 19:10:42 +02:00
Steven Rostedt (Red Hat)
b1169cc69b tracing: Remove mock up poll wait function
Now that the ring buffer has a built in way to wake up readers
when there's data, using irq_work such that it is safe to do it
in any context. But it was still using the old "poor man's"
wait polling that checks every 1/10 of a second to see if it
should wake up a waiter. This makes the latency for a wake up
excruciatingly long. No need to do that anymore.

Completely remove the different wait_poll types from the tracers
and have them all use the default one now.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-30 08:40:05 -04:00
Steven Rostedt (Red Hat)
f487426104 tracing: Break out of tracing_wait_pipe() before wait_pipe() is called
When reading from trace_pipe, if tracing is off but nothing was read
it should block. If something is read and tracing is off, then EOF
is returned. If tracing is on and there's nothing to read, it will block.

But because the check of whether tracing is off and something was read
is done after the block on the pipe, it is hit or miss if the EOF is
returned or not leading to inconsistent behavior.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-29 16:07:28 -04:00
Steven Rostedt (Red Hat)
a949ae560a ftrace/module: Hardcode ftrace_module_init() call into load_module()
A race exists between module loading and enabling of function tracer.

	CPU 1				CPU 2
	-----				-----
  load_module()
   module->state = MODULE_STATE_COMING

				register_ftrace_function()
				 mutex_lock(&ftrace_lock);
				 ftrace_startup()
				  update_ftrace_function();
				   ftrace_arch_code_modify_prepare()
				    set_all_module_text_rw();
				   <enables-ftrace>
				    ftrace_arch_code_modify_post_process()
				     set_all_module_text_ro();

				[ here all module text is set to RO,
				  including the module that is
				  loading!! ]

   blocking_notifier_call_chain(MODULE_STATE_COMING);
    ftrace_init_module()

     [ tries to modify code, but it's RO, and fails!
       ftrace_bug() is called]

When this race happens, ftrace_bug() will produces a nasty warning and
all of the function tracing features will be disabled until reboot.

The simple solution is to treate module load the same way the core
kernel is treated at boot. To hardcode the ftrace function modification
of converting calls to mcount into nops. This is done in init/main.c
there's no reason it could not be done in load_module(). This gives
a better control of the changes and doesn't tie the state of the
module to its notifiers as much. Ftrace is special, it needs to be
treated as such.

The reason this would work, is that the ftrace_module_init() would be
called while the module is in MODULE_STATE_UNFORMED, which is ignored
by the set_all_module_text_ro() call.

Link: http://lkml.kernel.org/r/1395637826-3312-1-git-send-email-indou.takao@jp.fujitsu.com

Reported-by: Takao Indoh <indou.takao@jp.fujitsu.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@vger.kernel.org # 2.6.38+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-28 10:37:21 -04:00
Jiaxing Wang
8d1b065d47 tracing: Fix documentation of ftrace_set_global_{filter,notrace}()
The functions ftrace_set_global_filter() and ftrace_set_global_notrace()
still have their old names in the kernel doc (ftrace_set_filter and
ftrace_set_notrace respectively). Replace these with the real names.

Link: http://lkml.kernel.org/p/1398006644-5935-3-git-send-email-wangjiaxing@insigma.com.cn

Signed-off-by: Jiaxing Wang <wangjiaxing@insigma.com.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-24 13:38:01 -04:00
Jiaxing Wang
7eea4fce02 tracing/stack_trace: Skip 4 instead of 3 when using ftrace_ops_list_func
When using ftrace_ops_list_func, we should skip 4 instead of 3,
to avoid ftrace_call+0x5/0xb appearing in the stack trace:

        Depth    Size   Location    (110 entries)
        -----    ----   --------
  0)     2956       0   update_curr+0xe/0x1e0
  1)     2956      68   ftrace_call+0x5/0xb
  2)     2888      92   enqueue_entity+0x53/0xe80
  3)     2796      80   enqueue_task_fair+0x47/0x7e0
  4)     2716      28   enqueue_task+0x45/0x70
  5)     2688      12   activate_task+0x22/0x30

Add a function using_ftrace_ops_list_func() to test for this while keeping
ftrace_ops_list_func to remain static.

Link: http://lkml.kernel.org/p/1398006644-5935-2-git-send-email-wangjiaxing@insigma.com.cn

Signed-off-by: Jiaxing Wang <wangjiaxing@insigma.com.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-24 13:36:03 -04:00
Masami Hiramatsu
3da0f18007 kprobes, ftrace: Use NOKPROBE_SYMBOL macro in ftrace
Use NOKPROBE_SYMBOL macro to protect functions from
kprobes instead of __kprobes annotation in ftrace.
This applies nokprobe_inline annotation for some cases,
because NOKPROBE_SYMBOL() will inhibit inlining by
referring the symbol address.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20140417081828.26341.55152.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-04-24 10:26:39 +02:00
Masami Hiramatsu
fbc1963d2c kprobes, ftrace: Allow probing on some functions
There is no need to prohibit probing on the functions
used for preparation and uprobe only fetch functions.
Those are safely probed because those are not invoked
from kprobe's breakpoint/fault/debug handlers. So there
is no chance to cause recursive exceptions.

Following functions are now removed from the kprobes blacklist:

	update_bitfield_fetch_param
	free_bitfield_fetch_param
	kprobe_register
	FETCH_FUNC_NAME(stack, type) in trace_uprobe.c
	FETCH_FUNC_NAME(memory, type) in trace_uprobe.c
	FETCH_FUNC_NAME(memory, string) in trace_uprobe.c
	FETCH_FUNC_NAME(memory, string_size) in trace_uprobe.c
	FETCH_FUNC_NAME(file_offset, type) in trace_uprobe.c

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20140417081800.26341.56504.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-04-24 10:03:02 +02:00
Fabian Frederick
ad1438a076 tracing: Add static to local functions
This patch adds static to the following functions:
-cycle_t buffer_ftrace_now
-void free_snapshot
-int trace_selftest_startup_dynamic_tracing

Link: http://lkml.kernel.org/p/20140417214442.d7abc7c0b0e4b90e7fedecc9@skynet.be

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-21 14:00:46 -04:00
Mathias Krause
8275f69f07 ftrace: Statically initialize pm notifier block
Instead of initializing the pm notifier block in register_ftrace_graph(),
initialize it statically. This safes us some code.

Found in the PaX patch, written by the PaX Team.

Link: http://lkml.kernel.org/p/1396186310-3156-1-git-send-email-minipli@googlemail.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: PaX Team <pageexec@freemail.hu>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-21 14:00:46 -04:00
Steven Rostedt (Red Hat)
02f2f7646f tracing: Allow irq/preempt tracers to be used by instances
The irqsoff, preemptoff and preemptirqsoff tracers can now be used by
instances. But they may only be used by one instance at a time (including
the top level directory). This allows multiple tracers to run while the
irqsoff (and friends) tracer is running simultaneously.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-21 13:59:29 -04:00
Steven Rostedt (Red Hat)
65daaca7c6 tracing: Allow wakeup tracers to be used by instances
The wakeup and wakeup_rt tracers can now be used by instances.
But they may only be used by one instance at a time (including the
top level directory). This allows multiple tracers to run while
the wakeup tracer is running simultaneously.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-21 13:59:28 -04:00
Steven Rostedt (Red Hat)
0b9b12c1b8 tracing: Move ftrace_max_lock into trace_array
In preparation for having tracers enabled in instances, the max_lock
should be unique as updating the max for one tracer is a separate
operation than updating it for another tracer using a different max.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-21 13:59:27 -04:00
Steven Rostedt (Red Hat)
6d9b3fa5e7 tracing: Move tracing_max_latency into trace_array
In preparation for letting the latency tracers be used by instances,
remove the global tracing_max_latency variable and add a max_latency
field to the trace_array that the latency tracers will now use.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-21 13:59:26 -04:00
Steven Rostedt (Red Hat)
4104d326b6 ftrace: Remove global function list and call function directly
Instead of having a list of global functions that are called,
as only one global function is allow to be enabled at a time, there's
no reason to have a list.

Instead, simply have all the users of the global ops, use the global ops
directly, instead of registering their own ftrace_ops. Just switch what
function is used before enabling the function tracer.

This removes a lot of code as well as the complexity involved with it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-21 13:59:25 -04:00
Linus Torvalds
7d77879bfd This contains two fixes.
The first is to remove a duplication of creating debugfs files that
 already exist and causes an error report to be printed due to the
 failure of the second creation.
 
 The second is a memory leak fix that was introduced in 3.14.
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Merge tag 'trace-fixes-v3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "This contains two fixes.

  The first is to remove a duplication of creating debugfs files that
  already exist and causes an error report to be printed due to the
  failure of the second creation.

  The second is a memory leak fix that was introduced in 3.14"

* tag 'trace-fixes-v3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing/uprobes: Fix uprobe_cpu_buffer memory leak
  tracing: Do not try to recreated toplevel set_ftrace_* files
2014-04-18 10:16:43 -07:00
zhangwei(Jovi)
6ea6215fe3 tracing/uprobes: Fix uprobe_cpu_buffer memory leak
Forgot to free uprobe_cpu_buffer percpu page in uprobe_buffer_disable().

Link: http://lkml.kernel.org/p/534F8B3F.1090407@huawei.com

Cc: stable@vger.kernel.org # v3.14+
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-17 10:44:42 -04:00
Steven Rostedt (Red Hat)
5d6c97c559 tracing: Do not try to recreated toplevel set_ftrace_* files
With the restructing of the function tracer working with instances, the
"top level" buffer is a bit special, as the function tracing is mapped
to the same set of filters. This is done by using a "global_ops" descriptor
and having the "set_ftrace_filter" and "set_ftrace_notrace" map to it.

When an instance is created, it creates the same files but its for the
local instance and not the global_ops.

The issues is that the local instance creation shares some code with
the global instance one and we end up trying to create th top level
"set_ftrace_*" files twice, and on boot up, we get an error like this:

 Could not create debugfs 'set_ftrace_filter' entry
 Could not create debugfs 'set_ftrace_notrace' entry

The reason they failed to be created was because they were created
twice, and the second time gives this error as you can not create the
same file twice.

Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-16 19:21:53 -04:00
Linus Torvalds
5166701b36 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "The first vfs pile, with deep apologies for being very late in this
  window.

  Assorted cleanups and fixes, plus a large preparatory part of iov_iter
  work.  There's a lot more of that, but it'll probably go into the next
  merge window - it *does* shape up nicely, removes a lot of
  boilerplate, gets rid of locking inconsistencie between aio_write and
  splice_write and I hope to get Kent's direct-io rewrite merged into
  the same queue, but some of the stuff after this point is having
  (mostly trivial) conflicts with the things already merged into
  mainline and with some I want more testing.

  This one passes LTP and xfstests without regressions, in addition to
  usual beating.  BTW, readahead02 in ltp syscalls testsuite has started
  giving failures since "mm/readahead.c: fix readahead failure for
  memoryless NUMA nodes and limit readahead pages" - might be a false
  positive, might be a real regression..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  missing bits of "splice: fix racy pipe->buffers uses"
  cifs: fix the race in cifs_writev()
  ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
  kill generic_file_buffered_write()
  ocfs2_file_aio_write(): switch to generic_perform_write()
  ceph_aio_write(): switch to generic_perform_write()
  xfs_file_buffered_aio_write(): switch to generic_perform_write()
  export generic_perform_write(), start getting rid of generic_file_buffer_write()
  generic_file_direct_write(): get rid of ppos argument
  btrfs_file_aio_write(): get rid of ppos
  kill the 5th argument of generic_file_buffered_write()
  kill the 4th argument of __generic_file_aio_write()
  lustre: don't open-code kernel_recvmsg()
  ocfs2: don't open-code kernel_recvmsg()
  drbd: don't open-code kernel_recvmsg()
  constify blk_rq_map_user_iov() and friends
  lustre: switch to kernel_sendmsg()
  ocfs2: don't open-code kernel_sendmsg()
  take iov_iter stuff to mm/iov_iter.c
  process_vm_access: tidy up a bit
  ...
2014-04-12 14:49:50 -07:00
Linus Torvalds
0a7418f5f5 This includes the final patch to clean up and fix the issue with the
design of tracepoints and how a user could register a tracepoint
 and have that tracepoint not be activated but no error was shown.
 
 The design was for an out of tree module but broke in tree users.
 The clean up was to remove the saving of the hash table of tracepoint
 names such that they can be enabled before they exist (enabling
 a module tracepoint before that module is loaded). This added more
 complexity than needed. The clean up was to remove that code and
 just enable tracepoints that exist or fail if they do not.
 
 This removed a lot of code as well as the complexity that it brought.
 As a side effect, instead of registering a tracepoint by its name,
 the tracepoint needs to be registered with the tracepoint descriptor.
 This removes having to duplicate the tracepoint names that are
 enabled.
 
 The second patch was added that simplified the way modules were
 searched for.
 
 This cleanup required changes that were in the 3.15 queue as well as
 some changes that were added late in the 3.14-rc cycle. This final
 change waited till the two were merged in upstream and then the
 change was added and full tests were run. Unfortunately, the
 test found some errors, but after it was already submitted to the
 for-next branch and not to be rebased. Sparse errors were detected
 by Fengguang Wu's bot tests, and my internal tests discovered that
 the anonymous union initialization triggered a bug in older gcc compilers.
 Luckily, there was a bugzilla for the gcc bug which gave a work around
 to the problem. The third and fourth patch handled the sparse error
 and the gcc bug respectively.
 
 A final patch was tagged along to fix a missing documentation for
 the README file.
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Merge tag 'trace-3.15-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull more tracing updates from Steven Rostedt:
 "This includes the final patch to clean up and fix the issue with the
  design of tracepoints and how a user could register a tracepoint and
  have that tracepoint not be activated but no error was shown.

  The design was for an out of tree module but broke in tree users.  The
  clean up was to remove the saving of the hash table of tracepoint
  names such that they can be enabled before they exist (enabling a
  module tracepoint before that module is loaded).  This added more
  complexity than needed.  The clean up was to remove that code and just
  enable tracepoints that exist or fail if they do not.

  This removed a lot of code as well as the complexity that it brought.
  As a side effect, instead of registering a tracepoint by its name, the
  tracepoint needs to be registered with the tracepoint descriptor.
  This removes having to duplicate the tracepoint names that are
  enabled.

  The second patch was added that simplified the way modules were
  searched for.

  This cleanup required changes that were in the 3.15 queue as well as
  some changes that were added late in the 3.14-rc cycle.  This final
  change waited till the two were merged in upstream and then the change
  was added and full tests were run.  Unfortunately, the test found some
  errors, but after it was already submitted to the for-next branch and
  not to be rebased.  Sparse errors were detected by Fengguang Wu's bot
  tests, and my internal tests discovered that the anonymous union
  initialization triggered a bug in older gcc compilers.  Luckily, there
  was a bugzilla for the gcc bug which gave a work around to the
  problem.  The third and fourth patch handled the sparse error and the
  gcc bug respectively.

  A final patch was tagged along to fix a missing documentation for the
  README file"

* tag 'trace-3.15-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Add missing function triggers dump and cpudump to README
  tracing: Fix anonymous unions in struct ftrace_event_call
  tracepoint: Fix sparse warnings in tracepoint.c
  tracepoint: Simplify tracepoint module search
  tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints
2014-04-12 13:06:10 -07:00
Al Viro
a786c06d9f missing bits of "splice: fix racy pipe->buffers uses"
that commit has fixed only the parts of that mess in fs/splice.c itself;
there had been more in several other ->splice_read() instances...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-12 07:04:19 -04:00
Steven Rostedt (Red Hat)
17a280ea81 tracing: Add missing function triggers dump and cpudump to README
The debugfs tracing README file lists all the function triggers except for
dump and cpudump. These should be added too.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-10 22:43:37 -04:00
Mathieu Desnoyers
abb43f6998 tracing: Fix anonymous unions in struct ftrace_event_call
gcc <= 4.5.x has significant limitations with respect to initialization
of anonymous unions within structures. They need to be surrounded by
brackets, _and_ they need to be initialized in the same order in which
they appear in the structure declaration.

Link: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10676
Link: http://lkml.kernel.org/r/1397077568-3156-1-git-send-email-mathieu.desnoyers@efficios.com

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-09 20:02:55 -04:00
Mathieu Desnoyers
de7b297390 tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints
Register/unregister tracepoint probes with struct tracepoint pointer
rather than tracepoint name.

This change, which vastly simplifies tracepoint.c, has been proposed by
Steven Rostedt. It also removes 8.8kB (mostly of text) to the vmlinux
size.

From this point on, the tracers need to pass a struct tracepoint pointer
to probe register/unregister. A probe can now only be connected to a
tracepoint that exists. Moreover, tracers are responsible for
unregistering the probe before the module containing its associated
tracepoint is unloaded.

   text    data     bss     dec     hex filename
10443444        4282528 10391552        25117524        17f4354 vmlinux.orig
10434930        4282848 10391552        25109330        17f2352 vmlinux

Link: http://lkml.kernel.org/r/1396992381-23785-2-git-send-email-mathieu.desnoyers@efficios.com

CC: Ingo Molnar <mingo@kernel.org>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Frank Ch. Eigler <fche@redhat.com>
CC: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
[ SDR - fixed return val in void func in tracepoint_module_going() ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-08 20:43:28 -04:00
Linus Torvalds
26c12d9334 Merge branch 'akpm' (incoming from Andrew)
Merge second patch-bomb from Andrew Morton:
 - the rest of MM
 - zram updates
 - zswap updates
 - exit
 - procfs
 - exec
 - wait
 - crash dump
 - lib/idr
 - rapidio
 - adfs, affs, bfs, ufs
 - cris
 - Kconfig things
 - initramfs
 - small amount of IPC material
 - percpu enhancements
 - early ioremap support
 - various other misc things

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (156 commits)
  MAINTAINERS: update Intel C600 SAS driver maintainers
  fs/ufs: remove unused ufs_super_block_third pointer
  fs/ufs: remove unused ufs_super_block_second pointer
  fs/ufs: remove unused ufs_super_block_first pointer
  fs/ufs/super.c: add __init to init_inodecache()
  doc/kernel-parameters.txt: add early_ioremap_debug
  arm64: add early_ioremap support
  arm64: initialize pgprot info earlier in boot
  x86: use generic early_ioremap
  mm: create generic early_ioremap() support
  x86/mm: sparse warning fix for early_memremap
  lglock: map to spinlock when !CONFIG_SMP
  percpu: add preemption checks to __this_cpu ops
  vmstat: use raw_cpu_ops to avoid false positives on preemption checks
  slub: use raw_cpu_inc for incrementing statistics
  net: replace __this_cpu_inc in route.c with raw_cpu_inc
  modules: use raw_cpu_write for initialization of per cpu refcount.
  mm: use raw_cpu ops for determining current NUMA node
  percpu: add raw_cpu_ops
  slub: fix leak of 'name' in sysfs_slab_add
  ...
2014-04-07 16:38:06 -07:00
Gideon Israel Dsouza
52f5684c8e kernel: use macros from compiler.h instead of __attribute__((...))
To increase compiler portability there is <linux/compiler.h> which
provides convenience macros for various gcc constructs.  Eg: __weak for
__attribute__((weak)).  I've replaced all instances of gcc attributes
with the right macro in the kernel subsystem.

Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:36:11 -07:00
Linus Torvalds
467a9e1633 CPU hotplug notifiers registration fixes for 3.15-rc1
The purpose of this single series of commits from Srivatsa S Bhat (with
 a small piece from Gautham R Shenoy) touching multiple subsystems that use
 CPU hotplug notifiers is to provide a way to register them that will not
 lead to deadlocks with CPU online/offline operations as described in the
 changelog of commit 93ae4f978c (CPU hotplug: Provide lockless versions
 of callback registration functions).
 
 The first three commits in the series introduce the API and document it
 and the rest simply goes through the users of CPU hotplug notifiers and
 converts them to using the new method.
 
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Merge tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull CPU hotplug notifiers registration fixes from Rafael Wysocki:
 "The purpose of this single series of commits from Srivatsa S Bhat
  (with a small piece from Gautham R Shenoy) touching multiple
  subsystems that use CPU hotplug notifiers is to provide a way to
  register them that will not lead to deadlocks with CPU online/offline
  operations as described in the changelog of commit 93ae4f978c ("CPU
  hotplug: Provide lockless versions of callback registration
  functions").

  The first three commits in the series introduce the API and document
  it and the rest simply goes through the users of CPU hotplug notifiers
  and converts them to using the new method"

* tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits)
  net/iucv/iucv.c: Fix CPU hotplug callback registration
  net/core/flow.c: Fix CPU hotplug callback registration
  mm, zswap: Fix CPU hotplug callback registration
  mm, vmstat: Fix CPU hotplug callback registration
  profile: Fix CPU hotplug callback registration
  trace, ring-buffer: Fix CPU hotplug callback registration
  xen, balloon: Fix CPU hotplug callback registration
  hwmon, via-cputemp: Fix CPU hotplug callback registration
  hwmon, coretemp: Fix CPU hotplug callback registration
  thermal, x86-pkg-temp: Fix CPU hotplug callback registration
  octeon, watchdog: Fix CPU hotplug callback registration
  oprofile, nmi-timer: Fix CPU hotplug callback registration
  intel-idle: Fix CPU hotplug callback registration
  clocksource, dummy-timer: Fix CPU hotplug callback registration
  drivers/base/topology.c: Fix CPU hotplug callback registration
  acpi-cpufreq: Fix CPU hotplug callback registration
  zsmalloc: Fix CPU hotplug callback registration
  scsi, fcoe: Fix CPU hotplug callback registration
  scsi, bnx2fc: Fix CPU hotplug callback registration
  scsi, bnx2i: Fix CPU hotplug callback registration
  ...
2014-04-07 14:55:46 -07:00
Linus Torvalds
2d1eb87ae1 Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM changes from Russell King:

 - Perf updates from Will Deacon:
   - Support for Qualcomm Krait processors (run perf on your phone!)
   - Support for Cortex-A12 (run perf stat on your FPGA!)
   - Support for perf_sample_event_took, allowing us to automatically decrease
     the sample rate if we can't handle the PMU interrupts quickly enough
     (run perf record on your FPGA!).

 - Basic uprobes support from David Long:
     This patch series adds basic uprobes support to ARM. It is based on
     patches developed earlier by Rabin Vincent. That approach of adding
     hooks into the kprobes instruction parsing code was not well received.
     This approach separates the ARM instruction parsing code in kprobes out
     into a separate set of functions which can be used by both kprobes and
     uprobes. Both kprobes and uprobes then provide their own semantic action
     tables to process the results of the parsing.

 - ARMv7M (microcontroller) updates from Uwe Kleine-König

 - OMAP DMA updates (recently added Vinod's Ack even though they've been
   sitting in linux-next for a few months) to reduce the reliance of
   omap-dma on the code in arch/arm.

 - SA11x0 changes from Dmitry Eremin-Solenikov and Alexander Shiyan

 - Support for Cortex-A12 CPU

 - Align support for ARMv6 with ARMv7 so they can cooperate better in a
   single zImage.

 - Addition of first AT_HWCAP2 feature bits for ARMv8 crypto support.

 - Removal of IRQ_DISABLED from various ARM files

 - Improved efficiency of virt_to_page() for single zImage

 - Patch from Ulf Hansson to permit runtime PM callbacks to be available for
   AMBA devices for suspend/resume as well.

 - Finally kill asm/system.h on ARM.

* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (89 commits)
  dmaengine: omap-dma: more consolidation of CCR register setup
  dmaengine: omap-dma: move IRQ handling to omap-dma
  dmaengine: omap-dma: move register read/writes into omap-dma.c
  ARM: omap: dma: get rid of 'p' allocation and clean up
  ARM: omap: move dma channel allocation into plat-omap code
  ARM: omap: dma: get rid of errata global
  ARM: omap: clean up DMA register accesses
  ARM: omap: remove almost-const variables
  ARM: omap: remove references to disable_irq_lch
  dmaengine: omap-dma: cleanup errata 3.3 handling
  dmaengine: omap-dma: provide register read/write functions
  dmaengine: omap-dma: use cached CCR value when enabling DMA
  dmaengine: omap-dma: move barrier to omap_dma_start_desc()
  dmaengine: omap-dma: move clnk_ctrl setting to preparation functions
  dmaengine: omap-dma: improve efficiency loading C.SA/C.EI/C.FI registers
  dmaengine: omap-dma: consolidate clearing channel status register
  dmaengine: omap-dma: move CCR buffering disable errata out of the fast path
  dmaengine: omap-dma: provide register definitions
  dmaengine: omap-dma: consolidate setup of CCR
  dmaengine: omap-dma: consolidate setup of CSDP
  ...
2014-04-05 13:20:43 -07:00