path: root/drivers/md
diff options
authorMikulas Patocka <>2021-05-10 14:49:05 -0400
committerMike Snitzer <>2021-05-13 14:42:52 -0400
commitc699a0db2d62e3bbb7f0bf35c87edbc8d23e3062 (patch)
tree22dff394ba42ecd8141bbd8ff8b6482df8de99e9 /drivers/md
parent7ee06ddc4038f936b0d4459d37a7d4d844fb03db (diff)
dm snapshot: fix crash with transient storage and zero chunk size
The following commands will crash the kernel: modprobe brd rd_size=1048576 dmsetup create o --table "0 `blockdev --getsize /dev/ram0` snapshot-origin /dev/ram0" dmsetup create s --table "0 `blockdev --getsize /dev/ram0` snapshot /dev/ram0 /dev/ram1 N 0" The reason is that when we test for zero chunk size, we jump to the label bad_read_metadata without setting the "r" variable. The function snapshot_ctr destroys all the structures and then exits with "r == 0". The kernel then crashes because it falsely believes that snapshot_ctr succeeded. In order to fix the bug, we set the variable "r" to -EINVAL. Signed-off-by: Mikulas Patocka <> Cc: Signed-off-by: Mike Snitzer <>
Diffstat (limited to 'drivers/md')
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 2a51ddd840b4..b8e4d31124ea 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1408,6 +1408,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
if (!s->store->chunk_size) {
ti->error = "Chunk size not set";
+ r = -EINVAL;
goto bad_read_metadata;