LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Punit Agrawal <punit.agrawal@arm.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Steve Capper <steve.capper@arm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andrei Vagin <avagin@gmail.com>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Cyrill Gorcunov <gorcunov@openvz.org>
Subject: Re: linux-next: BUG: Bad page state in process ip6tables-save pfn:1499f4
Date: Wed, 28 Jun 2017 12:32:12 +0100
Message-ID: <87fuekl54z.fsf@e105922-lin.cambridge.arm.com> (raw)
In-Reply-To: <20170627170408.4eowigh3pho2ph36@node.shutemov.name>

"Kirill A. Shutemov" <kirill@shutemov.name> writes:

> On Tue, Jun 27, 2017 at 05:53:59PM +0100, Punit Agrawal wrote:
>> "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> writes:
>> 
>> > On Tue, Jun 27, 2017 at 09:18:15AM +0200, Vlastimil Babka wrote:
>> >> On 06/24/2017 05:08 PM, Andrei Vagin wrote:
>> >> > On Fri, Jun 23, 2017 at 05:17:44PM -0700, Andrei Vagin wrote:
>> >> >> On Thu, Jun 22, 2017 at 11:21:03PM -0700, Andrei Vagin wrote:
>> >> >>> Hello,
>> >> >>>
>> >> >>> We run CRIU tests for linux-next and today they triggered a kernel
>> >> >>> bug. I want to mention that this kernel is built with kasan. This bug
>> >> >>> was triggered in travis-ci. I can't reproduce it on my host. Without
>> >> >>> kasan, kernel crashed but it is impossible to get a kernel log for
>> >> >>> this case.
>> >> >>
>> >> >> We use this tree
>> >> >> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/
>> >> >>
>> >> >> This issue isn't reproduced on the akpm-base branch and
>> >> >> it is reproduced each time on the akpm branch. I didn't
>> >> >> have time today to bisect it, will do on Monday.
>> >> > 
>> >> > c3aab7b2d4e8434d53bc81770442c14ccf0794a8 is the first bad commit
>> >> > 
>> >> > commit c3aab7b2d4e8434d53bc81770442c14ccf0794a8
>> >> > Merge: 849c34f 93a7379
>> >> > Author: Stephen Rothwell
>> >> > Date:   Fri Jun 23 16:40:07 2017 +1000
>> >> > 
>> >> >     Merge branch 'akpm-current/current'
>> >> 
>> >> Hm is it really the merge of mmotm itself and not one of the patches in
>> >> mmotm?
>> >> Anyway smells like THP, adding Kirill.
>> >
>> > Okay, it took a while to figure it out.
>> 
>> I'm sorry you had to go chasing for this one again.
>> 
>> I'd found the same issue while investigating an ltp failure on arm64[0] and
>> sent a fix[1]. The fix is effectively the same as your patch below.
>> 
>> Andrew picked up the patch from v5 posting and I can see it in today's
>> next[2].
>> 
>> 
>> [0] http://lists.infradead.org/pipermail/linux-arm-kernel/2017-June/510318.html
>> [1] https://patchwork.kernel.org/patch/9766193/
>> [2] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/mm/gup.c?h=next-20170627&id=d31945b5d4ab4490fb5f961dd5b066cc9f560eb3
>
> Ah. Okay, no problem then.
>
> But I think my fix is neater :)

Hehe.. I'm fine with either as they both fix the problem. :)

The reason I kept head and page initialisations separate is to ensure in
the future somebody doesn't conclude the page and head are the same -
which is true in most instances unless you've got contiguous hugepages
where that assumption breaks. But this isn't really full proof anyways.

  reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-23  6:21 Andrei Vagin
2017-06-24  0:17 ` Andrei Vagin
2017-06-24 15:08   ` Andrei Vagin
2017-06-27  7:18     ` Vlastimil Babka
2017-06-27 16:37       ` Kirill A. Shutemov
2017-06-27 16:53         ` Punit Agrawal
2017-06-27 17:04           ` Kirill A. Shutemov
2017-06-28 11:32             ` Punit Agrawal [this message]
2017-06-27 18:24           ` Andrei Vagin
2017-06-27 18:39         ` valdis.kletnieks

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=87fuekl54z.fsf@e105922-lin.cambridge.arm.com \
    --to=punit.agrawal@arm.com \
    --cc=akpm@linux-foundation.org \
    --cc=avagin@gmail.com \
    --cc=gorcunov@openvz.org \
    --cc=kirill.shutemov@linux.intel.com \
    --cc=kirill@shutemov.name \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=sfr@canb.auug.org.au \
    --cc=steve.capper@arm.com \
    --cc=vbabka@suse.cz \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org linux-kernel@archiver.kernel.org
	public-inbox-index lkml


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox