INFO: task syz.2.1039:12754 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.2.1039      state:D stack:27696 pid:12754 tgid:12752 ppid:10388  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x14ef/0x4fb0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7fe/0x1300
 sync_bdevs+0x27e/0x470
 __ia32_sys_sync+0xc5/0x120
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f938cd9acb9
RSP: 002b:00007f938dbc9028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f938d016090 RCX: 00007f938cd9acb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f938d016090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f938d016128 R14: 00007f938d016090 R15: 00007ffeb9070828
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5664:
 #0: ffff8881120fa0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900017802f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
5 locks held by kworker/1:3/5896:
 #0: ffff888168490d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0
 #1: ffffc90005507bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0
 #2: ffff88816c15f198 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30
 #3: ffff888173797198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
 #4: ffff888172f01160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
1 lock held by udevd/6174:
 #0: ffff88810a1a1358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
4 locks held by udevd/6526:
 #0: ffff8881a02a3c30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10
 #1: ffff888117c78888 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420
 #2: ffff888104fd5008 (kn->active#30){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420
 #3: ffff888173797198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0
1 lock held by syz.2.1039/12754:
 #0: ffff88810a1a1358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
1 lock held by syz.1.1122/13268:
 #0: ffff88810a1a1358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
1 lock held by syz-executor/15962:
 #0: ffff88816a7540e0 (&type->s_umount_key#85){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0

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

NMI backtrace for cpu 0
CPU: 0 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+0xf90/0xfe0
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 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: 15188 Comm: kworker/u9:15 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
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:filter_irq_stacks+0x3c/0xa0
Code: 89 fe 41 89 f4 31 db 49 bd 00 00 00 00 00 fc ff df 49 89 ff 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 34 8c 7b 00 <49> 8b 04 de 48 3d 30 02 00 81 0f 93 c1 48 3d 70 16 00 81 0f 92 c2
RSP: 0018:ffffc90003b07638 EFLAGS: 00000246
RAX: 1ffff92000760eda RBX: 0000000000000002 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 000000000000000a RDI: ffffc90003b076c0
RBP: ffffc90003b078f0 R08: 0000000000000014 R09: ffffffff8e35a360
R10: ffffc90003b075d8 R11: ffffffff81ae5d00 R12: 000000000000000a
R13: dffffc0000000000 R14: ffffc90003b076c0 R15: ffffc90003b076d0
FS:  0000000000000000(0000) GS:ffff8882a9924000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f709e2084f8 CR3: 000000011a834000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 stack_depot_save_flags+0x33/0x810
 kasan_save_track+0x4f/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 kmem_cache_free+0x195/0x610
 nsim_dev_trap_report_work+0x7cf/0xb80
 process_scheduled_works+0xaec/0x17a0
 worker_thread+0x89f/0xd90
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
