INFO: task poweroff:11673 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:poweroff        state:D stack:23992 pid:11673 tgid:11673 ppid:5280   task_flags:0x400000 flags:0x00004002
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 sync_bdevs+0x1ac/0x340
 ksys_sync+0xb9/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff4b75b97e7
RSP: 002b:00007ffdfcf0f4a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007ff4b75b97e7
RDX: 0000000000000078 RSI: 00007ff4b77488ca RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000001 R09: 00007ff4b77488ca
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdfcf0f5f8
R13: 00007ffdfcf0f608 R14: 00005604785ca169 R15: 00007ff4b7799a80
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: 
ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/u10:4/1140:
2 locks held by getty/5675:
 #0: ffff88802104e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by udevd/5850:
 #0: ffff88810775e358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
6 locks held by kworker/0:5/5906:
 #0: ffff88801bb01148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90003fafbc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888023e71198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
 #3: ffff88812e45b198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400
 #4: ffff8881069cc160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400
 #5: ffffffff8dfe0310 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xf0/0x2b0
2 locks held by kworker/u10:9/6521:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90002b6fbc0 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
1 lock held by poweroff/11673:
 #0: ffff88810775e358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.5.1006/12254:
 #0: ffff88810775e358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
2 locks held by syz-executor/12334:
 #0: ffff88803a20a0e0 (&type->s_umount_key#64){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0
 #1: ffff8881078127d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10
1 lock held by udevd/12336:
 #0: ffffffff8e6e3cc8 (uuid_mutex){+.+.}-{4:4}, at: btrfs_control_ioctl+0x111/0x360
1 lock held by syz.0.1236/13401:
 #0: ffff88810775e358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
3 locks held by syz.9.1404/14330:
 #0: ffff8880275920e0 (&type->s_umount_key#50/1){+.+.}-{4:4}, at: alloc_super+0x204/0x970
 #1: ffffffff8e1fe3e8 (lock#3){+.+.}-{4:4}, at: __lru_add_drain_all+0x66/0x5e0
 #2: ffff88804b039f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5830 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:native_apic_msr_write+0x39/0x50
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 cc cc cc cc cc f3 0f 1e fa 89 f6 31 d2 e9 92 9d 8e 03 66
RSP: 0018:ffffc900030afaf8 EFLAGS: 00000046
RAX: 000000000001000a RBX: ffff88804b023900 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 000000000001000a RDI: 0000000000000838
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff81ae022e
R10: 0000000000000003 R11: ffffffff81703490 R12: 00000000100006b5
R13: dffffc0000000000 R14: 000000000001000a R15: 0000000000000020
FS:  000055555c1a6500(0000) GS:ffff8880b861b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e320625888 CR3: 00000001120b6000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lapic_next_event+0x11/0x20
 clockevents_program_event+0x1cf/0x360
 hrtimer_start_range_ns+0xda6/0x1080
 do_nanosleep+0x191/0x600
 hrtimer_nanosleep+0x169/0x360
 __se_sys_clock_nanosleep+0x2f1/0x380
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0ada5c1463
Code: 1f 84 00 00 00 00 00 83 ff 03 74 7b 83 ff 02 b8 fa ff ff ff 49 89 ca 0f 44 f8 80 3d fe 70 1c 00 00 74 14 b8 e6 00 00 00 0f 05 <f7> d8 c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec 28 48 89 54 24 10
RSP: 002b:00007fffe2b5ce08 EFLAGS: 00000202 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0ada5c1463
RDX: 00007fffe2b5ce20 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000035742970 R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fffe2b5d270
R13: 0000000000000004 R14: 00007fffe2b5ce5c R15: 00007fffe2b5cef0
 </TASK>
