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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-06-10 22:53:37 +0200
committerIngo Molnar <mingo@elte.hu>2009-06-11 02:39:01 +0200
commit66fff22483d8542dfb4d61a28d21277bbde321e8 (patch)
tree615c582da3ef5bb75063467e82e9c63b010b535e /kernel/perf_counter.c
parentf7b7c26e01e51fe46097e11f179dc71ce7950084 (diff)
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>
Diffstat (limited to 'kernel/perf_counter.c')
-rw-r--r--kernel/perf_counter.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 51c571ee4d0..ae591a1275a 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -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,