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Commit 66fff224 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

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: default avatarPeter 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: default avatarIngo Molnar <mingo@elte.hu>
parent f7b7c26e

kernel/perf_counter.c

+12 −1
Original line number Original line Diff line number Diff line
@@ -3879,7 +3879,18 @@ void perf_counter_exit_task(struct task_struct *child) 
	spin_unlock(&child_ctx->lock);

	spin_unlock(&child_ctx->lock);

	local_irq_restore(flags);

	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:

again:

	list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list,

	list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list,