INFO: task syz.3.4683:18375 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.3.4683      state:D stack:24776 pid:18375 tgid:18374 ppid:8087   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7bf/0x1550
 sync_bdevs+0x276/0x470
 __ia32_sys_sync+0xc5/0x120
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f965cd9e0d9
RSP: 002b:00007f965dbd5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f965d025fa0 RCX: 00007f965cd9e0d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f965d025fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f965d026038 R14: 00007f965d025fa0 R15: 00007ffe23889ac8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8eb59ca0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
1 lock held by getty/5427:
5 locks held by kworker/0:3/5598:
 #0: ffff888168689540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc9000490fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffff88816bf4a1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30
 #3: ffff8881155d61d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0xfc/0x9a0
 #4: ffff88802232c1a0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880
5 locks held by kworker/0:8/10979:
 #0: ffff888168689540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc900094e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffff88816c0cb1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30
 #3: ffff88801ea841d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0xfc/0x9a0
 #4: ffff888020ffc1a0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880
1 lock held by udevd/14716:
 #0: ffff888108f18350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70
1 lock held by syz.3.4683/18375:
 #0: ffff888108f18350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x276/0x470
1 lock held by cxacru/19537:
 #0: ffffffff8e9f59c8 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xfc/0x2c0

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

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/0x380
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 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: 5427 Comm: getty 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:rep_movs_alternative+0x11/0xa0
Code: e9 04 65 04 00 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 83 f9 40 73 44 83 f9 08 73 25 85 c9 74 0f 8a 06 <88> 07 48 ff c7 48 ff c6 48 ff c9 75 f1 e9 cd 64 04 00 66 2e 0f 1f
RSP: 0018:ffffc9000407fab8 EFLAGS: 00000202
RAX: 00007ffffffff00a RBX: ffff888172677800 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 00007f35902b5252 RDI: ffff888172677800
RBP: ffffc9000407fc10 R08: ffff888172677800 R09: 1ffff1102e4cef00
R10: dffffc0000000000 R11: ffffed102e4cef01 R12: ffffc9000407fd78
R13: 00007f35902b5252 R14: 0000000000000001 R15: 1ffff9200080ffaf
FS:  00007f358ffc0380(0000) GS:ffff88818d952000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055854e0b9900 CR3: 000000011717a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 _copy_from_iter+0x21b/0x1660
 file_tty_write+0x487/0x9c0
 vfs_write+0x612/0xba0
 ksys_write+0x150/0x270
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3590114bf2
Code: 89 c7 48 89 44 24 08 e8 7b 34 fa ff 48 8b 44 24 08 48 83 c4 28 c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 6f 48 8b 15 07 a2 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffd344424d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f3590114bf2
RDX: 0000000000000001 RSI: 00007f35902b5252 RDI: 0000000000000001
RBP: 00007f35902b5252 R08: 0000000000005402 R09: 0000000000000000
R10: 00007ffd344424f4 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f358ffc0300 R14: 0000000000000000 R15: 000055c3cc5419ac
 </TASK>
