diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 1de17da34a95..a71277b640ab 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2137,6 +2137,8 @@ static int run(mddev_t *mddev)
 		    !test_bit(In_sync, &disk->rdev->flags)) {
 			disk->head_position = 0;
 			mddev->degraded++;
+			if (disk->rdev)
+				conf->fullsync = 1;
 		}
 	}
 
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c37e256b1176..475fba4d371e 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4305,7 +4305,9 @@ static int run(mddev_t *mddev)
 				" disk %d\n", bdevname(rdev->bdev,b),
 				raid_disk);
 			working_disks++;
-		}
+		} else
+			/* Cannot rely on bitmap to complete recovery */
+			conf->fullsync = 1;
 	}
 
 	/*