From mboxrd@z Thu Jan  1 00:00:00 1970
From: Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [4.9-rc3] BUG: unable to handle kernel paging request at ffffc900144dfc60
Date: Wed, 2 Nov 2016 08:54:43 -0600
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To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, Andrew Lutomirski <luto@kernel.org>, the arch/x86 maintainers <x86@kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Brian Gerst <brgerst@gmail.com>, Borislav Petkov <bp@alien8.de>, Jann Horn <jann@thejh.net>, Linux API <linux-api@vger.kernel.org>, Kees Cook <keescook@chromium.org>, Tycho Andersen <tycho.andersen@canonical.com>
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On Wed, Nov 2, 2016 at 4:50 AM, Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
>>
>> So I _think_ the fix is to just remove this. Perhaps something like
>> the attached? Adding scheduler people since this is in their code..
>
> That is not sufficient, for another Oops occurs inside stack_not_used().
> Since I don't want to break stack_not_used(), can we tolerate nested
> try_get_task_stack() usage and protect the whole sched_show_task()?

Sure, looks good to me.

But as Andy says, we should probably apply my patch too, just to get
rid of the useless hex printk and the ugly ifdeffery.

PeterZ/Ingo?

                Linus