From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Mon, 5 Dec 2016 05:26:38 +0000 (-0600)
Subject: dm space map: always set ev if sm_ll_mutate() succeeds
X-Git-Tag: v4.10-rc1~125^2~3
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b446396b7482938c859bfaa42320026d158616ae;p=karo-tx-linux.git

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>
---

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);
 }