INFO: task syz.4.922:10650 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.922       state:D stack:27904 pid:10650 tgid:10649 ppid:9882   task_flags:0x400140 flags:0x00004004
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/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1093d8ebe9
RSP: 002b:00007f1094bfe038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f1093fc5fa0 RCX: 00007f1093d8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f1093fc5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1093fc6038 R14: 00007f1093fc5fa0 R15: 00007ffeebd612b8
 </TASK>
INFO: task syz.4.922:10652 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.922       state:D stack:28296 pid:10652 tgid:10649 ppid:9882   task_flags:0x400040 flags:0x00004004
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/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1093d8ebe9
RSP: 002b:00007f1094bdd038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f1093fc6090 RCX: 00007f1093d8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f1093fc6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1093fc6128 R14: 00007f1093fc6090 R15: 00007ffeebd612b8
 </TASK>
INFO: task syz.4.922:10659 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.922       state:D stack:28296 pid:10659 tgid:10649 ppid:9882   task_flags:0x400040 flags:0x00004004
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/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1093d8ebe9
RSP: 002b:00007f1094bbc038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f1093fc6180 RCX: 00007f1093d8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f1093fc6180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1093fc6218 R14: 00007f1093fc6180 R15: 00007ffeebd612b8
 </TASK>
INFO: task syz.4.922:10663 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.922       state:D stack:28296 pid:10663 tgid:10649 ppid:9882   task_flags:0x400040 flags:0x00004004
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/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1093d8ebe9
RSP: 002b:00007f1094b9b038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f1093fc6270 RCX: 00007f1093d8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f1093fc6270 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1093fc6308 R14: 00007f1093fc6270 R15: 00007ffeebd612b8
 </TASK>
INFO: task syz.4.922:10664 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.922       state:D stack:28296 pid:10664 tgid:10649 ppid:9882   task_flags:0x400040 flags:0x00004004
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/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1093d8ebe9
RSP: 002b:00007f1094b7a038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f1093fc6360 RCX: 00007f1093d8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f1093fc6360 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1093fc63f8 R14: 00007f1093fc6360 R15: 00007ffeebd612b8
 </TASK>
INFO: task syz.4.922:10665 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.922       state:D stack:27904 pid:10665 tgid:10649 ppid:9882   task_flags:0x400040 flags:0x00004004
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/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1093d8ebe9
RSP: 002b:00007f1094b59038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f1093fc6450 RCX: 00007f1093d8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f1093fc6450 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1093fc64e8 R14: 00007f1093fc6450 R15: 00007ffeebd612b8
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:1/13:
 #0: ffff88801b6ff148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90000107ba0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f732950 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800
1 lock held by khungtaskd/34:
 #0: ffffffff8e33cda0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5671:
 #0: ffff8880273ee0a0 (&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
3 locks held by kworker/u8:2/5737:
 #0: ffff888136639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
 #1: ffff888136624008 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
 #2: ffff888136624008 (psi_seq){-.-.}-{0:0}, at: psi_task_change+0xd9/0x340
1 lock held by udevd/5919:
 #0: ffff88810765b358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
1 lock held by syz.4.922/10650:
 #0: ffff88810765b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.4.922/10652:
 #0: ffff88810765b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.4.922/10659:
 #0: ffff88810765b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.4.922/10663:
 #0: ffff88810765b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.4.922/10664:
 #0: ffff88810765b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.4.922/10665:
 #0: ffff88810765b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.6.1422/13004:
 #0: ffff88810765b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 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+0xf60/0xfa0
 kthread+0x711/0x8a0
 ret_from_fork+0x47f/0x820
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 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:pv_native_safe_halt+0x13/0x20
Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 33 91 29 00 f3 0f 1e fa fb f4 <e9> 08 e7 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000177de0 EFLAGS: 00000286
RAX: e9266e528bf17600 RBX: ffffffff81979518 RCX: e9266e528bf17600
RDX: 0000000000000001 RSI: ffffffff8dbbc9d5 RDI: ffffffff8c037100
RBP: ffffc90000177f10 R08: ffff888136632f9b R09: 1ffff11026cc65f3
R10: dffffc0000000000 R11: ffffed1026cc65f4 R12: ffffffff8fc3eb30
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110200d4000
FS:  0000000000000000(0000) GS:ffff8881a39fa000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3490dff8 CR3: 000000003c486000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 default_idle+0x13/0x20
 default_idle_call+0x74/0xb0
 do_idle+0x1e8/0x510
 cpu_startup_entry+0x44/0x60
 start_secondary+0x101/0x110
 common_startup_64+0x13e/0x147
 </TASK>
