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perf: Add a bit of paranoia

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Add a few WARN()s to catch things that should never happen.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150123125834.150481799@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2015-01-23 11:20:10 +01:00 committed by Ingo Molnar
parent 8f4bf4bcc4
commit 652884fe0c
1 changed files with 18 additions and 1 deletions
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19
kernel/events/core.c
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@ -1275,6 +1275,8 @@ static void perf_group_attach(struct perf_event *event)
if (group_leader == event) if (group_leader == event)
return; return;
WARN_ON_ONCE(group_leader->ctx != event->ctx);
if (group_leader->group_flags & PERF_GROUP_SOFTWARE && if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
!is_software_event(event)) !is_software_event(event))
group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
@ -1296,6 +1298,10 @@ static void
list_del_event(struct perf_event *event, struct perf_event_context *ctx) list_del_event(struct perf_event *event, struct perf_event_context *ctx)
{ {
struct perf_cpu_context *cpuctx; struct perf_cpu_context *cpuctx;
WARN_ON_ONCE(event->ctx != ctx);
lockdep_assert_held(&ctx->lock);
/* /*
* We can have double detach due to exit/hot-unplug + close. * We can have double detach due to exit/hot-unplug + close.
*/ */
@ -1380,6 +1386,8 @@ static void perf_group_detach(struct perf_event *event)
/* Inherit group flags from the previous leader */ /* Inherit group flags from the previous leader */
sibling->group_flags = event->group_flags; sibling->group_flags = event->group_flags;
WARN_ON_ONCE(sibling->ctx != event->ctx);
} }
out: out:
@ -1442,6 +1450,10 @@ event_sched_out(struct perf_event *event,
{ {
u64 tstamp = perf_event_time(event); u64 tstamp = perf_event_time(event);
u64 delta; u64 delta;
WARN_ON_ONCE(event->ctx != ctx);
lockdep_assert_held(&ctx->lock);
/* /*
* An event which could not be activated because of * An event which could not be activated because of
* filter mismatch still needs to have its timings * filter mismatch still needs to have its timings
@ -7822,14 +7834,19 @@ static void perf_free_event(struct perf_event *event,
put_event(parent); put_event(parent);
raw_spin_lock_irq(&ctx->lock);
perf_group_detach(event); perf_group_detach(event);
list_del_event(event, ctx); list_del_event(event, ctx);
raw_spin_unlock_irq(&ctx->lock);
free_event(event); free_event(event);
} }
/* /*
* free an unexposed, unused context as created by inheritance by * Free an unexposed, unused context as created by inheritance by
* perf_event_init_task below, used by fork() in case of fail. * perf_event_init_task below, used by fork() in case of fail.
*
* Not all locks are strictly required, but take them anyway to be nice and
* help out with the lockdep assertions.
*/ */
void perf_event_free_task(struct task_struct *task) void perf_event_free_task(struct task_struct *task)
{ {