On Mon 23-05-16 19:02:10, Vladimir Davydov wrote: > mem_cgroup_oom may be invoked multiple times while a process is handling > a page fault, in which case current->memcg_in_oom will be overwritten > leaking the previously taken css reference. Have you seen this happening? I was under impression that the page fault paths that have oom enabled will not retry allocations. > Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> That being said I do not have anything against the patch. It is a good safety net I am just not sure this might happen right now and so the patch is not stable candidate. After clarification Acked-by: Michal Hocko <mhocko@xxxxxxxx> > --- > mm/memcontrol.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 5b48cd25951b..ef8797d34039 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1608,7 +1608,7 @@ static void memcg_oom_recover(struct mem_cgroup *memcg) > > static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) > { > - if (!current->memcg_may_oom) > + if (!current->memcg_may_oom || current->memcg_in_oom) > return; > /* > * We are in the middle of the charge context here, so we > -- > 2.1.4 -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>