From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm: memcg: do not declare OOM from __GFP_NOFAIL allocations
84235de394d9 ("fs: buffer: move allocation failure loop into the
allocator") started recognizing __GFP_NOFAIL in memory cgroups but forgot
to disable the OOM killer.
Any task that does not fail allocation will also not enter the OOM
completion path. So don't declare an OOM state in this case or it'll be
leaked and the task be able to bypass the limit until the next
userspace-triggered page fault cleans up the OOM state.
Reported-by: William Dauchy <wdauchy@xxxxxxxxx>
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [3.12.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN mm/memcontrol.c~mm-memcg-do-not-declare-oom-from-__gfp_nofail-allocations mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcg-do-not-declare-oom-from-__gfp_nofail-allocations
+++ a/mm/memcontrol.c
@@ -2696,6 +2696,9 @@ static int __mem_cgroup_try_charge(struc
if (unlikely(task_in_memcg_oom(current)))
goto bypass;
+ if (gfp_mask & __GFP_NOFAIL)
+ oom = false;
+
/*
* We always charge the cgroup the mm_struct belongs to.
* The mm_struct's mem_cgroup changes on task migration if the
_
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html