INFO: task syz.4.1797:19595 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.1797      state:D stack:28760 pid:19595 tgid:19592 ppid:15642  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x6d9/0x940
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x250
 __ia32_sys_sync+0xa0/0x120
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f695279cdd9
RSP: 002b:00007f69535c4028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f6952a16180 RCX: 00007f695279cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f6952a16180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6952a16218 R14: 00007f6952a16180 R15: 00007ffcc1ffc1e8
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
1 lock held by khungtaskd/34:
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/1:2/992:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffff88823c624588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
 #2: ffff888193709230 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x202/0x3d0
2 locks held by getty/5440:
 #0: ffff888113d850a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000346b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
5 locks held by kworker/u8:3/5669:
 #0: ffff8881012b5940 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc900048f7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffffffff8fdbfdc8 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800
 #3: ffff8881a8485590 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_destruct+0x116/0x310
 #4: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
2 locks held by syz-executor/18447:
1 lock held by syz.4.1797/19595:
 #0: ffff88816b9700d8 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.2.2099/22132:
 #0: ffff88816b9700d8 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x289/0x3d0
8 locks held by syz-executor/22741:
 #0: ffff888114952410 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90
 #1: ffff88819d6bec80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540
 #2: ffff88816b73bb48 (kn->active#48){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540
 #3: ffffffff8f64e6e0 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370
 #4: ffff8881bae8c128 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x870
 #5: ffff8881bae88258 (&devlink->lock_key#46){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x170
 #6: ffffffff8fdcea80 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x13a/0x830
 #7: ffff88819d77cdc8 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0x588/0x22c0
1 lock held by syz.6.2181/22783:

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

NMI backtrace for cpu 1
CPU: 1 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+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: 22741 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:__lock_acquire+0x197b/0x2cf0
Code: 14 25 ff 0f 00 00 39 05 8f ec 9e 12 73 06 89 05 87 ec 9e 12 48 8b 02 48 89 df 4c 39 e8 0f 84 2c fe ff ff 4c 89 60 30 48 8b 00 <4c> 39 e8 75 f4 48 89 df e9 18 fe ff ff 48 89 fb 48 c7 c7 10 af 82
RSP: 0018:ffffc90006d86c68 EFLAGS: 00000002
RAX: ffffffff96efe938 RBX: 00000000000003fd RCX: 000000000000065e
RDX: ffffffff96dba4e8 RSI: ffff888104706618 RDI: 00000000000003fd
RBP: 8a794fb329962b62 R08: ffffc90006d86c30 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff81a20c90 R12: ffffffff96dba558
R13: ffffffff93e988b8 R14: ffff888104705880 R15: 000000000000065d
FS:  0000555573580500(0000) GS:ffff88818dc93000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2b74d8 CR3: 00000000126c0000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x350
 _raw_spin_lock_irqsave+0x40/0x60
 debug_object_deactivate+0x6c/0x3a0
 hrtimer_try_to_cancel+0x34e/0x670
 update_curr_dl_se+0x307/0x1260
 update_curr+0x1fa/0x4e0
 enqueue_task_fair+0x442/0x2aa0
 enqueue_task+0x75/0x410
 ttwu_do_activate+0x1cc/0x660
 try_to_wake_up+0x724/0x1380
 kick_pool+0x47d/0x640
 __queue_work+0xcdc/0xfc0
 queue_work_on+0x106/0x1d0
 nf_nat_masq_schedule+0x532/0x6e0
 masq_device_event+0xa2/0xe0
 notifier_call_chain+0x1ad/0x3d0
 netif_close_many+0x2ae/0x420
 unregister_netdevice_many_notify+0x825/0x22c0
 unregister_netdevice_queue+0x31f/0x360
 nsim_destroy+0x24e/0x830
 __nsim_dev_port_del+0x14f/0x200
 nsim_dev_reload_destroy+0x288/0x490
 nsim_drv_remove+0x58/0x170
 device_release_driver_internal+0x46f/0x870
 bus_remove_device+0x455/0x570
 device_del+0x527/0x8f0
 device_unregister+0x21/0xf0
 del_device_store+0x2b0/0x370
 kernfs_fop_write_iter+0x3af/0x540
 vfs_write+0x61d/0xb90
 ksys_write+0x150/0x270
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f70eb55d60e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffefc86f218 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555573580500 RCX: 00007f70eb55d60e
RDX: 0000000000000001 RSI: 00007ffefc86f2a0 RDI: 0000000000000005
RBP: 00007f70eb6335ec R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffefc86f2a0 R14: 00007f70ec344620 R15: 0000000000000003
 </TASK>
