diff --git a/drivers/md/bcache/closure.c b/drivers/md/bcache/closure.c
index 73f5319295bc..c12cd809ab19 100644
--- a/drivers/md/bcache/closure.c
+++ b/drivers/md/bcache/closure.c
@@ -105,8 +105,14 @@ struct closure_syncer {
 
 static void closure_sync_fn(struct closure *cl)
 {
-	cl->s->done = 1;
-	wake_up_process(cl->s->task);
+	struct closure_syncer *s = cl->s;
+	struct task_struct *p;
+
+	rcu_read_lock();
+	p = READ_ONCE(s->task);
+	s->done = 1;
+	wake_up_process(p);
+	rcu_read_unlock();
 }
 
 void __sched __closure_sync(struct closure *cl)