On Thu, Feb 17, 2022 at 03:34:13PM +0800, Jason Wang
wrote:> On Thu, Feb 17, 2022 at 10:01 AM syzbot
> <syzbot+1e3ea63db39f2b4440e0 at syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit: c5d9ae265b10 Merge tag 'for-linus' of
git://git.kernel.org..
> > git tree: upstream
> > console output:
https://syzkaller.appspot.com/x/log.txt?x=132e687c700000
> > kernel config:
https://syzkaller.appspot.com/x/.config?x=a78b064590b9f912
> > dashboard link:
https://syzkaller.appspot.com/bug?extid=1e3ea63db39f2b4440e0
> > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU
Binutils for Debian) 2.35.2
> >
> > Unfortunately, I don't have any reproducer for this issue yet.
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the
commit:
> > Reported-by: syzbot+1e3ea63db39f2b4440e0 at syzkaller.appspotmail.com
> >
> > WARNING: CPU: 1 PID: 10828 at drivers/vhost/vhost.c:715
vhost_dev_cleanup+0x8b8/0xbc0 drivers/vhost/vhost.c:715
> > Modules linked in:
> > CPU: 0 PID: 10828 Comm: syz-executor.0 Not tainted
5.17.0-rc4-syzkaller-00051-gc5d9ae265b10 #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine,
BIOS Google 01/01/2011
> > RIP: 0010:vhost_dev_cleanup+0x8b8/0xbc0 drivers/vhost/vhost.c:715
>
> Probably a hint that we are missing a flush.
>
> Looking at vhost_vsock_stop() that is called by vhost_vsock_dev_release():
>
> static int vhost_vsock_stop(struct vhost_vsock *vsock)
> {
> size_t i;
> int ret;
>
> mutex_lock(&vsock->dev.mutex);
>
> ret = vhost_dev_check_owner(&vsock->dev);
> if (ret)
> goto err;
>
> Where it could fail so the device is not actually stopped.
>
> I wonder if this is something related.
>
> Thanks
But then if that is not the owner then no work should be running, right?
>
> > Code: c7 85 90 01 00 00 00 00 00 00 e8 53 6e a2 fa 48 89 ef 48 83 c4
20 5b 5d 41 5c 41 5d 41 5e 41 5f e9 7d d6 ff ff e8 38 6e a2 fa <0f> 0b e9
46 ff ff ff 48 8b 7c 24 10 e8 87 00 ea fa e9 75 f7 ff ff
> > RSP: 0018:ffffc9000fe6fa18 EFLAGS: 00010293
> > RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
> > RDX: ffff888021b63a00 RSI: ffffffff86d66fe8 RDI: ffff88801cc200b0
> > RBP: ffff88801cc20000 R08: 0000000000000001 R09: 0000000000000001
> > R10: ffffffff817f1e08 R11: 0000000000000000 R12: ffff88801cc200d0
> > R13: ffff88801cc20120 R14: ffff88801cc200d0 R15: 0000000000000002
> > FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000)
knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 0000001b2de25000 CR3: 000000004c9cd000 CR4: 00000000003506f0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > Call Trace:
> > <TASK>
> > vhost_vsock_dev_release+0x36e/0x4b0 drivers/vhost/vsock.c:771
> > __fput+0x286/0x9f0 fs/file_table.c:313
> > task_work_run+0xdd/0x1a0 kernel/task_work.c:164
> > exit_task_work include/linux/task_work.h:32 [inline]
> > do_exit+0xb29/0x2a30 kernel/exit.c:806
> > do_group_exit+0xd2/0x2f0 kernel/exit.c:935
> > get_signal+0x45a/0x2490 kernel/signal.c:2863
> > arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868
> > handle_signal_work kernel/entry/common.c:148 [inline]
> > exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
> > exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207
> > __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
> > syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
> > do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > RIP: 0033:0x7f4027a46481
> > Code: Unable to access opcode bytes at RIP 0x7f4027a46457.
> > RSP: 002b:00007f402808ba68 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
> > RAX: fffffffffffffffc RBX: 00007f402622e700 RCX: 00007f4027a46481
> > RDX: 00007f402622e9d0 RSI: 00007f402622e2f0 RDI: 00000000003d0f00
> > RBP: 00007f402808bcb0 R08: 00007f402622e700 R09: 00007f402622e700
> > R10: 00007f402622e9d0 R11: 0000000000000206 R12: 00007f402808bb1e
> > R13: 00007f402808bb1f R14: 00007f402622e300 R15: 0000000000022000
> > </TASK>
> >
> >
> > ---
> > This report is generated by a bot. It may contain errors.
> > See https://goo.gl/tpsmEJ for more information about syzbot.
> > syzbot engineers can be reached at syzkaller at googlegroups.com.
> >
> > syzbot will keep track of this issue. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> >