syzbot

INFO: task syz-executor397:6534 blocked for more than 143 seconds.
      Not tainted 5.16.0-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor397 state:D stack:28112 pid: 6534 ppid:  3637 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4986 [inline]
 __schedule+0xab2/0x4f00 kernel/sched/core.c:6296
 schedule+0xd2/0x260 kernel/sched/core.c:6369
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6428
 __mutex_lock_common kernel/locking/mutex.c:673 [inline]
 __mutex_lock+0xa32/0x12f0 kernel/locking/mutex.c:733
 vhost_net_stop_vq drivers/vhost/net.c:1359 [inline]
 vhost_net_stop+0x142/0x270 drivers/vhost/net.c:1373
 vhost_net_release+0x9c/0x2d0 drivers/vhost/net.c:1405
 __fput+0x286/0x9f0 fs/file_table.c:280
 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
 __do_sys_exit_group kernel/exit.c:946 [inline]
 __se_sys_exit_group kernel/exit.c:944 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:944
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fcf820a5b39
RSP: 002b:00007ffe5f066dd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fcf8211a330 RCX: 00007fcf820a5b39
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 00007ffe5f066fc8
R10: 00007ffe5f066fc8 R11: 0000000000000246 R12: 00007fcf8211a330
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8bb85320 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6460
2 locks held by getty/3287:
 #0: ffff888023d6d098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
 #1: ffffc90002b632e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2077
1 lock held by syz-executor397/6534:
 #0: ffff8880772a0218 (&vq->mutex){+.+.}-{3:3}, at: vhost_net_stop_vq drivers/vhost/net.c:1359 [inline]
 #0: ffff8880772a0218 (&vq->mutex){+.+.}-{3:3}, at: vhost_net_stop+0x142/0x270 drivers/vhost/net.c:1373
1 lock held by vhost-6534/6535:

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xc1d/0xf50 kernel/hung_task.c:295
 kthread+0x2e9/0x3a0 kernel/kthread.c:359
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 6535 Comm: vhost-6534 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x60 kernel/kcov.c:200
Code: 81 e1 00 01 00 00 65 48 8b 14 25 00 70 02 00 a9 00 01 ff 00 74 0e 85 c9 74 35 8b 82 a4 15 00 00 85 c0 74 2b 8b 82 80 15 00 00 <83> f8 02 75 20 48 8b 8a 88 15 00 00 8b 92 84 15 00 00 48 8b 01 48
RSP: 0018:ffffc9000349faf0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888075a09d00 RSI: ffffffff86d68eb7 RDI: 0000000000000003
RBP: dffffc0000000000 R08: 000000000000000f R09: ffffc9000349fb27
R10: ffffffff86d68ea9 R11: 0000000000000001 R12: ffff88801d905c00
R13: 000000000000000f R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c7fbe99f10 CR3: 0000000074ff4000 CR4: 0000000000350ee0
Call Trace:
 <TASK>
 vhost_iotlb_itree_subtree_search drivers/vhost/iotlb.c:19 [inline]
 vhost_iotlb_itree_iter_first drivers/vhost/iotlb.c:19 [inline]
 vhost_iotlb_itree_first+0x177/0x280 drivers/vhost/iotlb.c:169
 iotlb_access_ok+0x1ce/0x3e0 drivers/vhost/vhost.c:1336
 vq_meta_prefetch+0xbc/0x280 drivers/vhost/vhost.c:1366
 handle_rx+0x145/0x1b40 drivers/vhost/net.c:1140
 vhost_worker+0x23d/0x3d0 drivers/vhost/vhost.c:372
 kthread+0x2e9/0x3a0 kernel/kthread.c:359
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
----------------
Code disassembly (best guess):
   0:	81 e1 00 01 00 00    	and    $0x100,%ecx
   6:	65 48 8b 14 25 00 70 	mov    %gs:0x27000,%rdx
   d:	02 00
   f:	a9 00 01 ff 00       	test   $0xff0100,%eax
  14:	74 0e                	je     0x24
  16:	85 c9                	test   %ecx,%ecx
  18:	74 35                	je     0x4f
  1a:	8b 82 a4 15 00 00    	mov    0x15a4(%rdx),%eax
  20:	85 c0                	test   %eax,%eax
  22:	74 2b                	je     0x4f
  24:	8b 82 80 15 00 00    	mov    0x1580(%rdx),%eax
* 2a:	83 f8 02             	cmp    $0x2,%eax <-- trapping instruction
  2d:	75 20                	jne    0x4f
  2f:	48 8b 8a 88 15 00 00 	mov    0x1588(%rdx),%rcx
  36:	8b 92 84 15 00 00    	mov    0x1584(%rdx),%edx
  3c:	48 8b 01             	mov    (%rcx),%rax
  3f:	48                   	rex.W