diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 86ba7851e881..e93f6aacfcd7 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2049,15 +2049,16 @@ static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
 static int grow_stripes(struct r5conf *conf, int num)
 {
 	struct kmem_cache *sc;
+	size_t namelen = sizeof(conf->cache_name[0]);
 	int devs = max(conf->raid_disks, conf->previous_raid_disks);
 
 	if (conf->mddev->gendisk)
-		sprintf(conf->cache_name[0],
+		snprintf(conf->cache_name[0], namelen,
 			"raid%d-%s", conf->level, mdname(conf->mddev));
 	else
-		sprintf(conf->cache_name[0],
+		snprintf(conf->cache_name[0], namelen,
 			"raid%d-%p", conf->level, conf->mddev);
-	sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);
+	snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
 
 	conf->active_name = 0;
 	sc = kmem_cache_create(conf->cache_name[conf->active_name],