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perf_counter: Annotate exit ctx recursion 

Ever since Paul fixed it to unclone the context before taking the
ctx->lock this became a false positive, annotate it away.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-06-10 22:53:37 +02:00 committed by Ingo Molnar
parent f7b7c26e01
commit 66fff22483
1 changed files with 12 additions and 1 deletions
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13
kernel/perf_counter.c
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@ -3879,7 +3879,18 @@ void perf_counter_exit_task(struct task_struct *child)
spin_unlock(&child_ctx->lock);
local_irq_restore(flags);
mutex_lock(&child_ctx->mutex);
/*
* We can recurse on the same lock type through:
*
* __perf_counter_exit_task()
* sync_child_counter()
* fput(parent_counter->filp)
* perf_release()
* mutex_lock(&ctx->mutex)
*
* But since its the parent context it won't be the same instance.
*/
mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
again:
list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list,