1 files changed, 12 insertions, 5 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 142dbabc1615..f773fa13d7c2 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -947,7 +947,8 @@ static void put_ctx(struct perf_event_context *ctx)
  *          perf_event::mmap_mutex
  *          mmap_sem
  */
-static struct perf_event_context *perf_event_ctx_lock(struct perf_event *event)
+static struct perf_event_context *
+perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
 {
         struct perf_event_context *ctx;
 
@@ -960,7 +961,7 @@ again:
         }
         rcu_read_unlock();
 
-        mutex_lock(&ctx->mutex);
+        mutex_lock_nested(&ctx->mutex, nesting);
         if (event->ctx != ctx) {
                 mutex_unlock(&ctx->mutex);
                 put_ctx(ctx);
@@ -970,6 +971,12 @@ again:
         return ctx;
 }
 
+static inline struct perf_event_context *
+perf_event_ctx_lock(struct perf_event *event)
+{
+        return perf_event_ctx_lock_nested(event, 0);
+}
+
 static void perf_event_ctx_unlock(struct perf_event *event,
                                   struct perf_event_context *ctx)
 {
@@ -3572,7 +3579,7 @@ static void perf_remove_from_owner(struct perf_event *event)
  */
 static void put_event(struct perf_event *event)
 {
-        struct perf_event_context *ctx = event->ctx;
+        struct perf_event_context *ctx;
 
         if (!atomic_long_dec_and_test(&event->refcount))
                 return;
@@ -3580,7 +3587,6 @@ static void put_event(struct perf_event *event)
         if (!is_kernel_event(event))
                 perf_remove_from_owner(event);
 
-        WARN_ON_ONCE(ctx->parent_ctx);
         /*
          * There are two ways this annotation is useful:
          *
@@ -3593,7 +3599,8 @@ static void put_event(struct perf_event *event)
          *     the last filedesc died, so there is no possibility
          *     to trigger the AB-BA case.
          */
-        mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
+        ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
+        WARN_ON_ONCE(ctx->parent_ctx);
         perf_remove_from_context(event, true);
         mutex_unlock(&ctx->mutex);