[patch] mm: memcg: make sure memory.events is uptodate when waking pollers fix

[Johannes Weiner]

On Fri, Apr 06, 2018 at 02:53:30PM +1000, Stephen Rothwell wrote:
> Hi Andrew,
> 
> After merging the akpm-current tree, today's linux-next build (x86_64
> allmodconfig) produced this warning:
> 
> mm/memcontrol.c: In function 'memory_events_show':
> mm/memcontrol.c:5453:23: warning: array subscript is above array bounds 
> [-Warray-bounds]
>       atomic_long_read(&memcg->memory_events[OOM_KILL]));
>                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Introduced by commit
> 
>   725844c87a0d ("mm: memcg: make sure memory.events is uptodate when waking 
> pollers")

Ah, silly, I missed that warning. The below fixes it.

Signed-off-by: Johannes Weiner <han...@cmpxchg.org>
---

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 04ea2b104ee2..9bac6dc26e09 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5199,8 +5199,7 @@ static int memory_events_show(struct seq_file *m, void *v)
                   atomic_long_read(&memcg->memory_events[MEMCG_MAX]));
        seq_printf(m, "oom %lu\n",
                   atomic_long_read(&memcg->memory_events[MEMCG_OOM]));
-       seq_printf(m, "oom_kill %lu\n",
-                  atomic_long_read(&memcg->memory_events[OOM_KILL]));
+       seq_printf(m, "oom_kill %lu\n", memcg_sum_events(memcg, OOM_KILL));
 
        return 0;
 }