perf: Ensure we call add_event_to_ctx() with the right locks held

Even though we call it from the inherit path, where the child is
not yet accessible, we need to hold ctx->lock, add_event_to_ctx()
assumes IRQs are disabled.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-09-10 12:51:54 +02:00 committed by Ingo Molnar
parent 3b8fad3e2f
commit cee010ec52

View File

@ -5913,6 +5913,7 @@ inherit_event(struct perf_event *parent_event,
struct perf_event_context *child_ctx)
{
struct perf_event *child_event;
unsigned long flags;
/*
* Instead of creating recursive hierarchies of events,
@ -5957,7 +5958,9 @@ inherit_event(struct perf_event *parent_event,
/*
* Link it up in the child's context:
*/
raw_spin_lock_irqsave(&child_ctx->lock, flags);
add_event_to_ctx(child_event, child_ctx);
raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
/*
* Get a reference to the parent filp - we will fput it