diff --git a/drivers/md/md.c b/drivers/md/md.c
index 8d11cd1a0d8b..6eb95451f161 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4639,6 +4639,11 @@ static int update_size(mddev_t *mddev, sector_t num_sectors)
 	 */
 	if (mddev->sync_thread)
 		return -EBUSY;
+	if (mddev->bitmap)
+		/* Sorry, cannot grow a bitmap yet, just remove it,
+		 * grow, and re-add.
+		 */
+		return -EBUSY;
 	rdev_for_each(rdev, tmp, mddev) {
 		sector_t avail;
 		avail = rdev->size * 2;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 40e939675657..17e0953c3c06 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4446,6 +4446,9 @@ static int raid5_check_reshape(mddev_t *mddev)
 		return -EINVAL; /* Cannot shrink array or change level yet */
 	if (mddev->delta_disks == 0)
 		return 0; /* nothing to do */
+	if (mddev->bitmap)
+		/* Cannot grow a bitmap yet */
+		return -EBUSY;
 
 	/* Can only proceed if there are plenty of stripe_heads.
 	 * We need a minimum of one full stripe,, and for sensible progress