path: root/drivers/md
diff options
authorMikulas Patocka <>2021-05-25 13:17:19 -0400
committerMike Snitzer <>2021-05-25 16:19:58 -0400
commit7e768532b2396bcb7fbf6f82384b85c0f1d2f197 (patch)
tree7397bddfe9ebf6e2f5586e805b00ae0532f67b76 /drivers/md
parentf16dba5dc6f094041ab8c356e1e3a48ee0e3c8cd (diff)
dm snapshot: properly fix a crash when an origin has no snapshots
If an origin target has no snapshots, o->split_boundary is set to 0. This causes BUG_ON(sectors <= 0) in block/bio.c:bio_split(). Fix this by initializing chunk_size, and in turn split_boundary, to rounddown_pow_of_two(UINT_MAX) -- the largest power of two that fits into "unsigned" type. Signed-off-by: Mikulas Patocka <> Cc: Signed-off-by: Mike Snitzer <>
Diffstat (limited to 'drivers/md')
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 75e59294ef77..751ec5ea1dbb 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -855,7 +855,7 @@ static int dm_add_exception(void *context, chunk_t old, chunk_t new)
static uint32_t __minimum_chunk_size(struct origin *o)
struct dm_snapshot *snap;
- unsigned chunk_size = 0;
+ unsigned chunk_size = rounddown_pow_of_two(UINT_MAX);
if (o)
list_for_each_entry(snap, &o->snapshots, list)