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| author | Peter Zijlstra <peterz@infradead.org> | 2015-11-30 12:56:15 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-12-04 10:08:03 +0100 |
| commit | 642c2d671ceff40e9453203ea0c66e991e11e249 (patch) | |
| tree | e02c733869c9c66e96f0a99d64bfde200a68ae7e | |
| parent | 90eec103b96e30401c0b846045bf8a1c7159b6da (diff) | |
| download | linux-642c2d671ceff40e9453203ea0c66e991e11e249.tar.gz linux-642c2d671ceff40e9453203ea0c66e991e11e249.tar.bz2 linux-642c2d671ceff40e9453203ea0c66e991e11e249.zip | |
perf: Fix PERF_EVENT_IOC_PERIOD deadlock
Dmitry reported a fairly silly recursive lock deadlock for
PERF_EVENT_IOC_PERIOD, fix this by explicitly doing the inactive part of
__perf_event_period() instead of calling that function.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: c7999c6f3fed ("perf: Fix PERF_EVENT_IOC_PERIOD migration race")
Link: http://lkml.kernel.org/r/20151130115615.GJ17308@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | kernel/events/core.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 5854fcf7f05a..49a5118f3564 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4225,7 +4225,14 @@ retry: goto retry; } - __perf_event_period(&pe); + if (event->attr.freq) { + event->attr.sample_freq = value; + } else { + event->attr.sample_period = value; + event->hw.sample_period = value; + } + + local64_set(&event->hw.period_left, 0); raw_spin_unlock_irq(&ctx->lock); return 0; |