mm, memcg: fix potential undefined behavior in mem_cgroup_event_ratelimit()

[mirror_ubuntu-artful-kernel.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a6eef3603b724d754a24fc5d20722871fd02d53c..3df3c04d73ab08e3bbb663f25b2e195b396d2149 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -631,7 +631,7 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
        val = __this_cpu_read(memcg->stat->nr_page_events);
        next = __this_cpu_read(memcg->stat->targets[target]);
        /* from time_after() in jiffies.h */
-       if ((long)next - (long)val < 0) {
+       if ((long)(next - val) < 0) {
                switch (target) {
                case MEM_CGROUP_TARGET_THRESH:
                        next = val + THRESHOLDS_EVENTS_TARGET;