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| author | Peter Zijlstra <peterz@infradead.org> | 2013-11-14 16:23:04 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-11-19 16:57:40 +0100 |
| commit | d5b5f391d434c5cc8bcb1ab2d759738797b85f52 (patch) | |
| tree | 9be9680fd08dd943cac38b278dde12d83b4a9856 /include/linux/tracepoint.h | |
| parent | 801a76050bcf8d4e500eb8d048ff6265f37a61c8 (diff) | |
| download | linux-d5b5f391d434c5cc8bcb1ab2d759738797b85f52.tar.gz linux-d5b5f391d434c5cc8bcb1ab2d759738797b85f52.tar.xz | |
ftrace, perf: Avoid infinite event generation loop
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:
,-> <IPI>
| 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 <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20131114152304.GC5364@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/tracepoint.h')
| -rw-r--r-- | include/linux/tracepoint.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index ebeab360d851..f16dc0a40049 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -267,6 +267,8 @@ static inline void tracepoint_synchronize_unregister(void) #define TRACE_EVENT_FLAGS(event, flag) +#define TRACE_EVENT_PERF_PERM(event, expr...) + #endif /* DECLARE_TRACE */ #ifndef TRACE_EVENT @@ -399,4 +401,6 @@ static inline void tracepoint_synchronize_unregister(void) #define TRACE_EVENT_FLAGS(event, flag) +#define TRACE_EVENT_PERF_PERM(event, expr...) + #endif /* ifdef TRACE_EVENT (see note above) */ |