diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 90fe70d76a3164ae8941e4a6f7d10418bd62afcd..87145faac491a865d8c2f45f87fdaa031e5b1b62 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1156,6 +1156,9 @@ static void bitmap_writeback_daemon(mddev_t *mddev)
 		err = -EINTR;
 		goto out;
 	}
+	if (bitmap == NULL)
+		/* about to be stopped. */
+		return;
 
 	PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
 	/* wait on bitmap page writebacks */