dm space map: always set ev if sm_ll_mutate() succeeds

If no block was allocated or freed, sm_ll_mutate() wasn't setting
*ev, leaving the variable unitialized. sm_ll_insert(),
sm_disk_inc_block(), and sm_disk_new_block() all check ev to see
if there was an allocation event in sm_ll_mutate(), possibly
reading unitialized data.

If no allocation event occured, sm_ll_mutate() should set *ev
to SM_NONE.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/md/persistent-data/dm-space-map-common.c b/drivers/md/persistent-data/dm-space-map-common.c
index 10978ba1d2c1..4c28608a0c94 100644
--- a/drivers/md/persistent-data/dm-space-map-common.c
+++ b/drivers/md/persistent-data/dm-space-map-common.c
@@ -464,7 +464,8 @@ static int sm_ll_mutate(struct ll_disk *ll, dm_block_t b,
                 ll->nr_allocated--;
                 le32_add_cpu(&ie_disk.nr_free, 1);
                 ie_disk.none_free_before = cpu_to_le32(min(le32_to_cpu(ie_disk.none_free_before), bit));
-        }
+        } else
+                *ev = SM_NONE;
 
         return ll->save_ie(ll, index, &ie_disk);
 }