Messages in this thread | | | Subject | Re: INFO: task hung in vhost_net_stop_vq | From | Jason Wang <> | Date | Tue, 26 Mar 2019 18:17:26 +0800 |
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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")
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