From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
syzbot <syzbot+d21e6e297322a900c128@syzkaller.appspotmail.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com,
virtualization@lists.linux-foundation.org, weiyj.lk@gmail.com
Subject: Re: INFO: task hung in vhost_net_stop_vq
Date: Tue, 26 Mar 2019 18:17:26 +0800 [thread overview]
Message-ID: <df4f2cf6-8469-f894-8f45-7c48a6a1801f@redhat.com> (raw)
In-Reply-To: <20190325100223-mutt-send-email-mst@kernel.org>
On 2019/3/25 下午10:02, Michael S. Tsirkin wrote:
> Looks like more iotlb locking mess?
Looking at the calltrace:
[ 221.743675] =============================================
[ 221.744297] [ INFO: possible recursive locking detected ]
[ 221.744944] 4.7.0+ #1 Not tainted
[ 221.745326] ---------------------------------------------
[ 221.746128] syz-executor1/6823 is trying to acquire lock:
[ 221.746737] (&vq->mutex){+.+...}, at: [<ffffffff84484b70>] vhost_process_iotlb_msg+0xe0/0x9e0
[ 221.747789]
[ 221.747789] but task is already holding lock:
[ 221.748470] (&vq->mutex){+.+...}, at: [<ffffffff84484b70>] vhost_process_iotlb_msg+0xe0/0x9e0
[ 221.749535]
[ 221.749535] other info that might help us debug this:
[ 221.750280] Possible unsafe locking scenario:
[ 221.750280]
[ 221.750946] CPU0
[ 221.751232] ----
[ 221.751523] lock(&vq->mutex);
[ 221.751922] lock(&vq->mutex);
[ 221.752339]
[ 221.752339] *** DEADLOCK ***
[ 221.752339]
I could not think of a path that can hit this. And I could not reproduce with the reproducer in the link in net-next.
Thanks
>
> On Tue, Mar 19, 2019 at 10:21:00PM -0700, syzbot wrote:
>> syzbot has bisected this bug to:
>>
>> commit 6b1e6cc7855b09a0a9bfa1d9f30172ba366f161c
>> Author: Jason Wang <jasowang@redhat.com>
>> Date: Thu Jun 23 06:04:32 2016 +0000
>>
>> vhost: new device IOTLB API
>>
>> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1486ad27200000
>> start commit: 6b1e6cc7 vhost: new device IOTLB API
>> git tree: upstream
>> final crash: https://syzkaller.appspot.com/x/report.txt?x=1686ad27200000
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1286ad27200000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=c94f9f0c0363db4b
>> dashboard link: https://syzkaller.appspot.com/bug?extid=d21e6e297322a900c128
>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=141db34d400000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=108ef293400000
>>
>> Reported-by: syzbot+d21e6e297322a900c128@syzkaller.appspotmail.com
>> Fixes: 6b1e6cc7 ("vhost: new device IOTLB API")
next prev parent reply other threads:[~2019-03-26 10:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-30 22:32 INFO: task hung in vhost_net_stop_vq syzbot
2019-03-20 5:21 ` syzbot
2019-03-25 14:02 ` Michael S. Tsirkin
2019-03-26 10:17 ` Jason Wang [this message]
2019-03-26 10:28 ` Dmitry Vyukov
2019-04-09 3:31 ` Jason Wang
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