From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Hillf Danton <hdanton@sina.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
syzbot <syzbot+c48f34012b06c4ac67dd@syzkaller.appspotmail.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
syzkaller-bugs@googlegroups.com,
Mike Kravetz <mike.kravetz@oracle.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Jens Axboe <axboe@kernel.dk>,
Markus Elfring <Markus.Elfring@web.de>
Subject: Re: kernel BUG at include/linux/swapops.h:LINE!
Date: Fri, 24 Jul 2020 14:13:11 +0300 [thread overview]
Message-ID: <20200724111311.rcjqigtjqpkenxg6@box> (raw)
In-Reply-To: <20200723073744.5268-1-hdanton@sina.com>
On Thu, Jul 23, 2020 at 03:37:44PM +0800, Hillf Danton wrote:
>
> On Tue, 21 Jul 2020 14:11:31 +0300 Kirill A. Shutemov wrote:
> > On Mon, Jul 20, 2020 at 04:51:44PM -0700, Andrew Morton wrote:
> > > On Sun, 19 Jul 2020 14:10:19 -0700 syzbot wrote:
> > >
> > > > syzbot has found a reproducer for the following issue on:
> > > >
> > > > HEAD commit: 4c43049f Add linux-next specific files for 20200716
> > > > git tree: linux-next
> > > > console output: https://syzkaller.appspot.com/x/log.txt?x=12c56087100000
> > > > kernel config: https://syzkaller.appspot.com/x/.config?x=2c76d72659687242
> > > > dashboard link: https://syzkaller.appspot.com/bug?extid=c48f34012b06c4ac67dd
> > > > compiler: gcc (GCC) 10.1.0-syz 20200507
> > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1344abeb100000
> > > >
> > > > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > > > Reported-by: syzbot+c48f34012b06c4ac67dd@syzkaller.appspotmail.com
> > >
> > > Thanks.
> > >
> > > __handle_mm_fault
> > > ->pmd_migration_entry_wait
> > > ->migration_entry_to_page
> > >
> > > stumbled onto an unlocked page.
> > >
> > > I don't immediately see a cause. Perhaps Matthew's "THP prep patches",
> > > perhaps something else.
> > >
> > > Is it possible to perform a bisection?
> >
> > Maybe it's related to the new lock_page_async()?
>
> Or is there likely the window that after copy_huge_pmd() the src pmd migrate
> entry is removed and the page unlocked but the dst is not?
No.
copy_huge_pmd() runs with exclusive mmap_lock on the source side and
destination side is not running yet.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2020-07-24 11:13 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-30 17:05 kernel BUG at include/linux/swapops.h:LINE! syzbot
2020-07-19 21:10 ` syzbot
2020-07-20 23:51 ` Andrew Morton
2020-07-21 0:21 ` Matthew Wilcox
2020-07-21 2:14 ` Matthew Wilcox
2020-07-21 11:11 ` Kirill A. Shutemov
2020-07-21 15:11 ` Jens Axboe
[not found] ` <20200723073744.5268-1-hdanton@sina.com>
2020-07-24 11:13 ` Kirill A. Shutemov [this message]
2020-07-26 16:49 ` Matthew Wilcox
2020-07-27 10:31 ` Kirill A. Shutemov
2020-07-27 12:03 ` Matthew Wilcox
2020-07-29 19:21 ` Kirill A. Shutemov
2020-07-29 19:54 ` Matthew Wilcox
2020-07-29 22:11 ` Matthew Wilcox
[not found] ` <20200727125950.12048-1-hdanton@sina.com>
2020-07-27 13:44 ` Matthew Wilcox
2021-05-08 11:24 ` [syzbot] " syzbot
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