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yaml --- r: 147715 b: refs/heads/master c: 66fff22 h: refs/heads/master i: 147713: 546043d 147711: fb128f4 v: v3
git-mirror · Jun 11, 2009 · 02420a2 · 02420a2
1 parent 0f0976b
commit 02420a2
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Showing 2 changed files with 13 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f7b7c26e01e51fe46097e11f179dc71ce7950084
+refs/heads/master: 66fff22483d8542dfb4d61a28d21277bbde321e8
diff --git a/trunk/kernel/perf_counter.c b/trunk/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,