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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: mhocko@kernel.org, akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.com
Subject: Re: [PATCH] oom, oom_reaper: Do not enqueue task if it is on the oom_reaper_list head
Date: Tue, 29 Mar 2016 21:52:20 +0900	[thread overview]
Message-ID: <201603292152.IBF60927.FJOHMVtOFOFSQL@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <1459254686-29457-1-git-send-email-mhocko@kernel.org>

Michal Hocko wrote:
> From: Michal Hocko <mhocko@suse.com>
> 
> bb29902a7515 ("oom, oom_reaper: protect oom_reaper_list using simpler
> way") has simplified the check for tasks already enqueued for the oom
> reaper by checking tsk->oom_reaper_list != NULL. This check is not
> sufficient because the tsk might be the head of the queue without any
> other tasks queued and then we would simply lockup looping on the same
> task. Fix the condition by checking for the head as well.

Indeed, oom_reaper_list is initially NULL.

> 
> Fixes: bb29902a7515 ("oom, oom_reaper: protect oom_reaper_list using simpler way")
> Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

> ---
> Hi,
> I have just noticed this after I started consolidating other oom_reaper
> related changes I have here locally. I should have caught this during
> the review already and I really feel ashamed I haven't because this is
> really a trivial bug that should be obvious see...

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      reply	other threads:[~2016-03-29 12:52 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-29 12:31 Michal Hocko
2016-03-29 12:52 ` Tetsuo Handa [this message]

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