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From:   Naresh Kamboju <naresh.kamboju@linaro.org>
Date:   Fri, 22 May 2020 21:11:53 +0530
Message-ID: <CA+G9fYvw+oY-EK1+FYCUAD5-UGD4MhBGJHasjF+L5nLtzL2GLQ@mail.gmail.com>
Subject: Re: [PATCH v3 2/2] mm, memcg: Decouple e{low,min} state mutations
 from protection checks
To:     Chris Down <chris@chrisdown.name>
Cc:     Yafang Shao <laoar.shao@gmail.com>,
        Michal Hocko <mhocko@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Roman Gushchin <guro@fb.com>, linux-mm <linux-mm@kvack.org>,
        Cgroups <cgroups@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        lkft-triage@lists.linaro.org
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On Fri, 22 May 2020 at 17:15, Chris Down <chris@chrisdown.name> wrote:
>
> Naresh Kamboju writes:
> >This patch is causing oom-killer while running mkfs -t ext4 on i386 kernel
> >running on x86_64 machine version linux-next 5.7.0-rc6-next-20200521.
>
> I think I see what's wrong here -- if we bail out early, memory.e{min,low}
> might be uninitialised.
>
> Does this patch fix it, by any chance?
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index d3b23c57bed4..aa902b9cbb79 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -5046,6 +5046,9 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
>                         memory_cgrp_subsys.broken_hierarchy = true;
>         }
>
> +       memcg->memory.emin = 0;
> +       memcg->memory.elow = 0;
> +
>         /* The following stuff does not apply to the root */
>         if (!parent) {
>   #ifdef CONFIG_MEMCG_KMEM

This patch did not fix the problem.
The test log showing oom-killer link,
https://lkft.validation.linaro.org/scheduler/job/1445128#L1194

Build images:
https://builds.tuxbuild.com/YqW37GVsCHf8ndxOT2z1iQ/

- Naresh