diff --git a/drivers/md/md.c b/drivers/md/md.c
index 8cc4bbcf9bf8bde3ccad4134e9694344b920683e..06f6e81f1516c16fb48f08dbe7a8781f5271563f 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8694,6 +8694,11 @@ static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev)
 				ret = remove_and_add_spares(mddev, rdev2);
 				pr_info("Activated spare: %s\n",
 						bdevname(rdev2->bdev,b));
+				/* wakeup mddev->thread here, so array could
+				 * perform resync with the new activated disk */
+				set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+				md_wakeup_thread(mddev->thread);
+
 			}
 			/* device faulty
 			 * We just want to do the minimum to mark the disk