From: Colin Ian King <colin.king@canonical.com>
Date: Sat, 11 Mar 2017 19:09:45 +0000 (+0000)
Subject: dm cache: handle kmalloc failure allocating background_tracker struct
X-Git-Tag: MMI-PSA29.97-13-9~5578^2
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7e1b9521f5a8356553f5e58b07952bf346632ea4;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

dm cache: handle kmalloc failure allocating background_tracker struct

Currently there is no kmalloc failure check on the allocation of
the background_tracker struct in btracker_create(), and so a NULL return
will lead to a NULL pointer dereference.  Add a NULL check.

Detected by CoverityScan, CID#1416587 ("Dereference null return value")

Fixes: b29d4986d ("dm cache: significant rework to leverage dm-bio-prison-v2")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---

diff --git a/drivers/md/dm-cache-background-tracker.c b/drivers/md/dm-cache-background-tracker.c
index 9b1afdfb13f0..707233891291 100644
--- a/drivers/md/dm-cache-background-tracker.c
+++ b/drivers/md/dm-cache-background-tracker.c
@@ -33,6 +33,11 @@ struct background_tracker *btracker_create(unsigned max_work)
 {
 	struct background_tracker *b = kmalloc(sizeof(*b), GFP_KERNEL);
 
+	if (!b) {
+		DMERR("couldn't create background_tracker");
+		return NULL;
+	}
+
 	b->max_work = max_work;
 	atomic_set(&b->pending_promotes, 0);
 	atomic_set(&b->pending_writebacks, 0);