diff --git a/[refs] b/[refs]
index 5e8965b6b56f..558767697379 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d0985394e7fee6b25a7cc8335d45bc1c1a8ab2d3
+refs/heads/master: 7a401a972df8e184b3d1a3fc958c0a4ddee8d312
diff --git a/trunk/mm/backing-dev.c b/trunk/mm/backing-dev.c
index a0860640378d..71034f41a2ba 100644
--- a/trunk/mm/backing-dev.c
+++ b/trunk/mm/backing-dev.c
@@ -724,6 +724,14 @@ void bdi_destroy(struct backing_dev_info *bdi)
 
 	bdi_unregister(bdi);
 
+	/*
+	 * If bdi_unregister() had already been called earlier, the
+	 * wakeup_timer could still be armed because bdi_prune_sb()
+	 * can race with the bdi_wakeup_thread_delayed() calls from
+	 * __mark_inode_dirty().
+	 */
+	del_timer_sync(&bdi->wb.wakeup_timer);
+
 	for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
 		percpu_counter_destroy(&bdi->bdi_stat[i]);