INFO: task syz.7.779:9604 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.779       state:D stack:25528 pid:9604  tgid:9603  ppid:9264   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7f7/0x1550
 sync_bdevs+0x27e/0x470
 __ia32_sys_sync+0xc5/0x120
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7d5819cdd9
RSP: 002b:00007f7d590e3028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7d58415fa0 RCX: 00007f7d5819cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7d58415fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7d58416038 R14: 00007f7d58415fa0 R15: 00007fff1c4a8e88
 </TASK>
INFO: task syz.7.779:9631 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.779       state:D stack:28280 pid:9631  tgid:9603  ppid:9264   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7f7/0x1550
 sync_bdevs+0x27e/0x470
 __ia32_sys_sync+0xc5/0x120
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7d5819cdd9
RSP: 002b:00007f7d590c2028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7d58416090 RCX: 00007f7d5819cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7d58416090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7d58416128 R14: 00007f7d58416090 R15: 00007fff1c4a8e88
 </TASK>
INFO: task syz.7.779:9633 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.779       state:D stack:27592 pid:9633  tgid:9603  ppid:9264   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7f7/0x1550
 sync_bdevs+0x27e/0x470
 __ia32_sys_sync+0xc5/0x120
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7d5819cdd9
RSP: 002b:00007f7d590a1028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7d58416180 RCX: 00007f7d5819cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7d58416180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7d58416218 R14: 00007f7d58416180 R15: 00007fff1c4a8e88
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5438:
 #0: ffff888115c420a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
1 lock held by udevd/5613:
 #0: ffff88810a87c350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
1 lock held by udevd/7907:
 #0: ffff88816a238350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
1 lock held by syz.7.779/9604:
 #0: ffff88810a87c350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
1 lock held by syz.7.779/9631:
 #0: ffff88810a87c350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
1 lock held by syz.7.779/9633:
 #0: ffff88810a87c350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
2 locks held by syz.4.1459/12847:
 #0: ffffffff8f84b460 (input_mutex){+.+.}-{4:4}, at: __input_unregister_device+0x2fa/0x610
 #1: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xfd3/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 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: 0 Comm: swapper/0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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+0xf/0x20
Code: eb 7d 02 e9 93 f6 02 00 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 53 b1 20 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8e607dc0 EFLAGS: 00000202
RAX: 000000000046da75 RBX: ffffffff819a91ea RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dfaa160 RDI: ffffffff8c28ade0
RBP: ffffffff8e607eb0 R08: ffff8881210339db R09: 1ffff1102420673b
R10: dffffc0000000000 R11: ffffed102420673c R12: 0000000000000000
R13: 1ffffffff1cd25d8 R14: 0000000000000000 R15: 1ffffffff1cd25d8
FS:  0000000000000000(0000) GS:ffff88818dc8d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f93ec21dff8 CR3: 00000001067c4000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 default_idle+0x9/0x20
 default_idle_call+0x72/0xb0
 do_idle+0x36a/0x5f0
 cpu_startup_entry+0x43/0x60
 rest_init+0x2de/0x300
 start_kernel+0x38a/0x3e0
 x86_64_start_reservations+0x24/0x30
 x86_64_start_kernel+0x143/0x1c0
 common_startup_64+0x13e/0x147
 </TASK>
