From: Jan Kara <jack@suse.cz>
To: syzbot <syzbot+87a05ae4accd500f5242@syzkaller.appspotmail.com>
Cc: ak@linux.intel.com, akpm@linux-foundation.org, jack@suse.cz,
jrdr.linux@gmail.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, mawilcox@microsoft.com,
mgorman@techsingularity.net, syzkaller-bugs@googlegroups.com,
tim.c.chen@linux.intel.com, zwisler@kernel.org
Subject: Re: linux-next test error
Date: Wed, 5 Sep 2018 10:55:45 +0200 [thread overview]
Message-ID: <20180905085545.GD24902@quack2.suse.cz> (raw)
In-Reply-To: <0000000000004f6b5805751a8189@google.com>
On Wed 05-09-18 00:13:02, syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 387ac6229ecf Add linux-next specific files for 20180905
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=149c67a6400000
> kernel config: https://syzkaller.appspot.com/x/.config?x=ad5163873ecfbc32
> dashboard link: https://syzkaller.appspot.com/bug?extid=87a05ae4accd500f5242
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+87a05ae4accd500f5242@syzkaller.appspotmail.com
>
> INFO: task hung in do_page_mkwriteINFO: task syz-fuzzer:4876 blocked for
> more than 140 seconds.
> Not tainted 4.19.0-rc2-next-20180905+ #56
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> syz-fuzzer D21704 4876 4871 0x00000000
> Call Trace:
> context_switch kernel/sched/core.c:2825 [inline]
> __schedule+0x87c/0x1df0 kernel/sched/core.c:3473
> schedule+0xfb/0x450 kernel/sched/core.c:3517
> io_schedule+0x1c/0x70 kernel/sched/core.c:5140
> wait_on_page_bit_common mm/filemap.c:1100 [inline]
> __lock_page+0x5b7/0x7a0 mm/filemap.c:1273
> lock_page include/linux/pagemap.h:483 [inline]
> do_page_mkwrite+0x429/0x520 mm/memory.c:2391
Waiting for page lock after ->page_mkwrite callback. Which means
->page_mkwrite did not return VM_FAULT_LOCKED but 0. Looking into
linux-next... indeed "fs: convert return type int to vm_fault_t" has busted
block_page_mkwrite(). It has to return VM_FAULT_LOCKED and not 0 now.
Souptick, can I ask you to run 'fstests' for at least common filesystems
like ext4, xfs, btrfs when you change generic filesystem code please? That
would catch a bug like this immediately. Thanks.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2018-09-05 8:55 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-05 7:13 linux-next test error syzbot
2018-09-05 7:17 ` Dmitry Vyukov
2018-09-05 8:55 ` Jan Kara [this message]
2018-09-05 9:50 ` Souptick Joarder
2018-09-05 9:53 ` Dmitry Vyukov
2018-09-05 9:57 ` Dmitry Vyukov
2018-09-05 13:34 ` Theodore Y. Ts'o
2018-09-05 18:44 ` Christoph Hellwig
2018-09-05 19:24 ` Souptick Joarder
2018-09-06 8:38 ` Jan Kara
2018-09-06 12:26 ` Souptick Joarder
2018-09-06 13:05 ` Matthew Wilcox
2018-09-06 13:12 ` Theodore Y. Ts'o
2018-09-06 14:07 ` Theodore Y. Ts'o
2018-09-06 16:00 ` Matthew Wilcox
2018-09-05 13:55 ` Jan Kara
2018-09-05 19:07 ` Souptick Joarder
2018-09-06 8:12 ` Jan Kara
2018-09-06 12:02 ` Souptick Joarder
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