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Date: Mon, 30 May 2016 08:52:13 +0200
From: Michal Hocko <mhocko@suse.cz>
Subject: Re: [PATCH] mm,oom_reaper: don't call mmput_async() without
 atomic_inc_not_zero()
Message-ID: <20160530065213.GC22928@dhcp22.suse.cz>
References: <1464423365-5555-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp>
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In-Reply-To: <1464423365-5555-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp>
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org, Arnd Bergmann <arnd@arndb.de>

On Sat 28-05-16 17:16:05, Tetsuo Handa wrote:
> Commit e2fe14564d3316d1 ("oom_reaper: close race with exiting task")
> reduced frequency of needlessly selecting next OOM victim, but was
> calling mmput_async() when atomic_inc_not_zero() failed.
> 
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>

Acked-by: Michal Hocko <mhocko@suse.com>

Thanks!

> ---
>  mm/oom_kill.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index dfb1ab6..0d781b8 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -478,6 +478,7 @@ static bool __oom_reap_task(struct task_struct *tsk)
>  	mm = p->mm;
>  	if (!atomic_inc_not_zero(&mm->mm_users)) {
>  		task_unlock(p);
> +		mm = NULL;
>  		goto unlock_oom;
>  	}
>  
> -- 
> 1.8.3.1
> 

-- 
Michal Hocko
SUSE Labs

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