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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 16 Jan 2018 11:34:46 -0800
Message-ID: <CA+55aFyxyjN0Mqnz66B4a0R+uR8DdfxdMhcg5rJVi8LwnpSRfA@mail.gmail.com>
Subject: Re: [mm 4.15-rc8] Random oopses under memory pressure.
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Sender: owner-linux-mm@kvack.org
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To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Dave Hansen <dave.hansen@linux.intel.com>, Ingo Molnar <mingo@kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, the arch/x86 maintainers <x86@kernel.org>, linux-fsdevel <linux-fsdevel@vger.kernel.org>, Michal Hocko <mhocko@kernel.org>

On Tue, Jan 16, 2018 at 9:33 AM, Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
>
> Since I got a faster reproducer, I tried full bisection between 4.11 and 4.12-rc1.
> But I have no idea why bisection arrives at c0332694903a37cf.

I don't think your reproducer is 100% reliable.

And bisection is great because it's very aggressive and optimal when
it comes to testing. But that also implies that if *any* of the
good/bad choices were incorrect, then the end result is pure garbage
and isn't even *close* to the right commit.

> It turned out that CONFIG_FLATMEM was irrelevant. I just did not hit it.

So have you actually been able to see the problem with FLATMEM, or is
this based on the bisect? Because I really think the bisect is pretty
much guaranteed to be wrong.

               Linus

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