1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 3fd8f0e169e7..4702f380cb45 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1189,6 +1189,21 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
                 goto out;
         }
 
+        /* Protect md->type against concurrent table loads. */
+        dm_lock_md_type(md);
+        if (dm_get_md_type(md) == DM_TYPE_NONE)
+                /* Initial table load: acquire type of table. */
+                dm_set_md_type(md, dm_table_get_type(t));
+        else if (dm_get_md_type(md) != dm_table_get_type(t)) {
+                DMWARN("can't change device type after initial table load.");
+                dm_table_destroy(t);
+                dm_unlock_md_type(md);
+                r = -EINVAL;
+                goto out;
+        }
+        dm_unlock_md_type(md);
+
+        /* stage inactive table */
         down_write(&_hash_lock);
         hc = dm_get_mdptr(md);
         if (!hc || hc->md != md) {