2 files changed, 8 insertions, 2 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 1510f78a0ffa..8f6185e69b69 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -126,6 +126,12 @@ static void __exit_signal(struct task_struct *tsk)
 
         __unhash_process(tsk);
 
+        /*
+         * Do this under ->siglock, we can race with another thread
+         * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
+         */
+        flush_sigqueue(&tsk->pending);
+
         tsk->signal = NULL;
         tsk->sighand = NULL;
         spin_unlock(&sighand->siglock);
@@ -133,7 +139,6 @@ static void __exit_signal(struct task_struct *tsk)
 
         __cleanup_sighand(sighand);
         clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
-        flush_sigqueue(&tsk->pending);
         if (sig) {
                 flush_sigqueue(&sig->shared_pending);
                 taskstats_tgid_free(sig);
diff --git a/kernel/signal.c b/kernel/signal.c
index 72bb4f51f963..12ffea7c201d 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1242,7 +1242,8 @@ void sigqueue_free(struct sigqueue *q)
         /*
          * If the signal is still pending remove it from the
          * pending queue. We must hold ->siglock while testing
-         * q->list to serialize with collect_signal().
+         * q->list to serialize with collect_signal() or with
+         * __exit_signal()->flush_sigqueue().
          */
         spin_lock_irqsave(lock, flags);
         if (!list_empty(&q->list))