linux-stable.git/include/trace/ftrace.h, branch v3.13.2

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2013-12-02T18:13:09+00:00

Pull perf fixes from Ingo Molnar:
 "Misc kernel and tooling fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tools lib traceevent: Fix conversion of pointer to integer of different size
  perf/trace: Properly use u64 to hold event_id
  perf: Remove fragile swevent hlist optimization
  ftrace, perf: Avoid infinite event generation loop
  tools lib traceevent: Fix use of multiple options in processing field
  perf header: Fix possible memory leaks in process_group_desc()
  perf header: Fix bogus group name
  perf tools: Tag thread comm as overriden

tracing: Allow events to have NULL strings

2013-11-26T15:34:46+00:00

If an TRACE_EVENT() uses __assign_str() or __get_str on a NULL pointer
then the following oops will happen:

BUG: unable to handle kernel NULL pointer dereference at   (null)
IP: [] strlen+0x10/0x1a
*pde = 00000000 ^M
Oops: 0000 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.13.0-rc1-test+ #2
Hardware name:                  /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006^M
task: f5cde9f0 ti: f5e5e000 task.ti: f5e5e000
EIP: 0060:[] EFLAGS: 00210046 CPU: 1
EIP is at strlen+0x10/0x1a
EAX: 00000000 EBX: c2472da8 ECX: ffffffff EDX: c2472da8
ESI: c1c5e5fc EDI: 00000000 EBP: f5e5fe84 ESP: f5e5fe80
 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
CR0: 8005003b CR2: 00000000 CR3: 01f32000 CR4: 000007d0
Stack:
 f5f18b90 f5e5feb8 c10687a8 0759004f 00000005 00000005 00000005 00200046
 00000002 00000000 c1082a93 f56c7e28 c2472da8 c1082a93 f5e5fee4 c106bc61^M
 00000000 c1082a93 00000000 00000000 00000001 00200046 00200082 00000000
Call Trace:
 [] ftrace_raw_event_lock+0x39/0xc0
 [] ? ktime_get+0x29/0x69
 [] ? ktime_get+0x29/0x69
 [] lock_release+0x57/0x1a5
 [] ? ktime_get+0x29/0x69
 [] read_seqcount_begin.constprop.7+0x4d/0x75
 [] ? ktime_get+0x29/0x69^M
 [] ktime_get+0x29/0x69
 [] __tick_nohz_idle_enter+0x1e/0x426
 [] ? lock_release_holdtime.part.19+0x48/0x4d
 [] ? time_hardirqs_off+0xe/0x28
 [] ? trace_hardirqs_off_caller+0x3f/0xaf
 [] tick_nohz_idle_enter+0x59/0x62
 [] cpu_startup_entry+0x64/0x192
 [] start_secondary+0x277/0x27c
Code: 90 89 c6 89 d0 88 c4 ac 38 e0 74 09 84 c0 75 f7 be 01 00 00 00 89 f0 48 5e 5d c3 55 89 e5 57 66 66 66 66 90 83 c9 ff 89 c7 31 c0  ae f7 d1 8d 41 ff 5f 5d c3 55 89 e5 57 66 66 66 66 90 31 ff
EIP: [] strlen+0x10/0x1a SS:ESP 0068:f5e5fe80
CR2: 0000000000000000
---[ end trace 01bc47bf519ec1b2 ]---

New tracepoints have been added that have allowed for NULL pointers
being assigned to strings. To fix this, change the TRACE_EVENT() code
to check for NULL and if it is, it will assign "(null)" to it instead
(similar to what glibc printf does).

Reported-by: Shuah Khan 
Reported-by: Jovi Zhangwei 
Link: http://lkml.kernel.org/r/CAGdX0WFeEuy+DtpsJzyzn0343qEEjLX97+o1VREFkUEhndC+5Q@mail.gmail.com
Link: http://lkml.kernel.org/r/528D6972.9010702@samsung.com
Fixes: 9cbf117662e2 ("tracing/events: provide string with undefined size support")
Cc: stable@vger.kernel.org # 2.6.31+
Signed-off-by: Steven Rostedt

ftrace, perf: Avoid infinite event generation loop

2013-11-19T15:57:40+00:00

Vince's perf-trinity fuzzer found yet another 'interesting' problem.

When we sample the irq_work_exit tracepoint with period==1 (or
PERF_SAMPLE_PERIOD) and we add an fasync SIGNAL handler we create an
infinite event generation loop:

  ,-> 
  |     irq_work_exit() ->
  |       trace_irq_work_exit() ->
  |         ...
  |           __perf_event_overflow() -> (due to fasync)
  |             irq_work_queue() -> (irq_work_list must be empty)
  '---------      arch_irq_work_raise()

Similar things can happen due to regular poll() wakeups if we exceed
the ring-buffer wakeup watermark, or have an event_limit.

To avoid this, dis-allow sampling this particular tracepoint.

In order to achieve this, create a special perf_perm function pointer
for each event and call this (when set) on trying to create a
tracepoint perf event.

[ roasted: use expr... to allow for ',' in your expression ]

Reported-by: Vince Weaver 
Tested-by: Vince Weaver 
Signed-off-by: Peter Zijlstra 
Cc: Steven Rostedt 
Cc: Dave Jones 
Cc: Frederic Weisbecker 
Link: http://lkml.kernel.org/r/20131114152304.GC5364@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar

tracing: Update event filters for multibuffer

2013-11-05T21:50:20+00:00

The trace event filters are still tied to event calls rather than
event files, which means you don't get what you'd expect when using
filters in the multibuffer case:

Before:

  # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  bytes_alloc > 8192
  # mkdir /sys/kernel/debug/tracing/instances/test1
  # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
  # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  bytes_alloc > 2048
  # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
  bytes_alloc > 2048

Setting the filter in tracing/instances/test1/events shouldn't affect
the same event in tracing/events as it does above.

After:

  # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  bytes_alloc > 8192
  # mkdir /sys/kernel/debug/tracing/instances/test1
  # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
  # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
  bytes_alloc > 8192
  # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
  bytes_alloc > 2048

We'd like to just move the filter directly from ftrace_event_call to
ftrace_event_file, but there are a couple cases that don't yet have
multibuffer support and therefore have to continue using the current
event_call-based filters.  For those cases, a new USE_CALL_FILTER bit
is added to the event_call flags, whose main purpose is to keep the
old behavior for those cases until they can be updated with
multibuffer support; at that point, the USE_CALL_FILTER flag (and the
new associated call_filter_check_discard() function) can go away.

The multibuffer support also made filter_current_check_discard()
redundant, so this change removes that function as well and replaces
it with filter_check_discard() (or call_filter_check_discard() as
appropriate).

Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi 
Signed-off-by: Steven Rostedt

tracing/perf: Avoid perf_trace_buf_*() in perf_trace_##call() when possible

2013-08-14T01:06:30+00:00

perf_trace_buf_prepare() + perf_trace_buf_submit(task => NULL)
make no sense if hlist_empty(head). Change perf_trace_##call()
to check ->perf_events beforehand and do nothing if it is empty.

This removes the overhead for tasks without events associated
with them. For example, "perf record -e sched:sched_switch -p1"
attaches the counter(s) to the single task, but every task in
system will do perf_trace_buf_prepare/submit() just to realize
that it was not attached to this event.

However, we can only do this if __task == NULL, so we also add
the __builtin_constant_p(__task) check.

With this patch "perf bench sched pipe" shows approximately 4%
improvement when "perf record -p1" runs in parallel, many thanks
to Steven for the testing.

Link: http://lkml.kernel.org/r/20130806160847.GA2746@redhat.com

Tested-by: David Ahern 
Acked-by: Peter Zijlstra 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt

tracing/perf: Reimplement TP_perf_assign() logic

2013-08-14T01:05:57+00:00

The next patch tries to avoid the costly perf_trace_buf_* calls
when possible but there is a problem. We can only do this if
__task == NULL, perf_tp_event(task != NULL) has the additional
code for this case.

Unfortunately, TP_perf_assign/__perf_xxx which changes the default
values of __count/__task variables for perf_trace_buf_submit() is
called "too late", after we already did perf_trace_buf_prepare(),
and the optimization above can't work.

So this patch simply embeds __perf_xxx() into TP_ARGS(), this way
DECLARE_EVENT_CLASS() can use the result of assignments hidden in
"args" right after ftrace_get_offsets_##call() which is mostly
trivial. This allows us to have the fast-path "__task != NULL"
check at the start, see the next patch.

Link: http://lkml.kernel.org/r/20130806160844.GA2739@redhat.com

Tested-by: David Ahern 
Acked-by: Peter Zijlstra 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt

tracing/perf: Expand TRACE_EVENT(sched_stat_runtime)

2013-08-14T01:05:12+00:00

To simplify the review of the next patches:

1. We are going to reimplent __perf_task/counter and embedd them
   into TP_ARGS(). expand TRACE_EVENT(sched_stat_runtime) into
   DECLARE_EVENT_CLASS() + DEFINE_EVENT(), this way they can use
   different TP_ARGS's.

2. Change perf_trace_##call() macro to do perf_fetch_caller_regs()
   right before perf_trace_buf_prepare().

   This way it evaluates TP_ARGS() asap, the next patch explores
   this fact.

   Note: after 87f44bbc perf_trace_buf_prepare() doesn't need
   "struct pt_regs *regs", perhaps it makes sense to remove this
   argument. And perhaps we can teach perf_trace_buf_submit()
   to accept regs == NULL and do fetch_caller_regs(CALLER_ADDR1)
   in this case.

3. Cosmetic, but the typecast from "void*" buys nothing. It just
   adds the noise, remove it.

Link: http://lkml.kernel.org/r/20130806160841.GA2736@redhat.com

Acked-by: Peter Zijlstra 
Tested-by: David Ahern 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt

tracing/perf: Move the PERF_MAX_TRACE_SIZE check into perf_trace_buf_prepare()

2013-07-19T01:31:28+00:00

Every perf_trace_buf_prepare() caller does
WARN_ONCE(size > PERF_MAX_TRACE_SIZE, message) and "message" is
almost the same.

Shift this WARN_ONCE() into perf_trace_buf_prepare(). This changes
the meaning of _ONCE, but I think this is fine.

	- 4947014 2932448 10104832  17984294  1126b26 vmlinux
	+ 4948422 2932448 10104832  17985702  11270a6 vmlinux

on my build.

Link: http://lkml.kernel.org/r/20130617170211.GA19813@redhat.com

Acked-by: Peter Zijlstra 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt

tracing: Add DEFINE_EVENT_FN() macro

2013-06-21T05:24:32+00:00

Each TRACE_EVENT() adds several helper functions. If two or more trace events
share the same structure and print format, they can also share most of these
helper functions and save a lot of space from duplicate code. This is why the
DECLARE_EVENT_CLASS() and DEFINE_EVENT() were created.

Some events require a trigger to be called at registering and unregistering of
the event and to do so they use TRACE_EVENT_FN().

If multiple events require a trigger, they currently have no choice but to use
TRACE_EVENT_FN() as there's no DEFINE_EVENT_FN() available. This unfortunately
causes a lot of wasted duplicate code created.

By adding a DEFINE_EVENT_FN(), these events can still use a
DECLARE_EVENT_CLASS() and then define their own triggers.

Signed-off-by: Steven Rostedt 
Link: http://lkml.kernel.org/r/51C3236C.8030508@hds.com
Signed-off-by: Seiji Aguchi 
Signed-off-by: H. Peter Anvin

tracing: Remove obsolete macro guard _TRACE_PROFILE_INIT

2013-04-13T03:02:33+00:00

The macro _TRACE_PROFILE_INIT was removed a long time ago,
but an "#undef" guard was left behind. Remove it.

Link: http://lkml.kernel.org/r/514684EE.6000805@huawei.com

Signed-off-by: zhangwei(Jovi) 
Signed-off-by: Steven Rostedt