INFO: task syz.9.682:11979 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.682       state:D stack:23944 pid:11979 tgid:11902 ppid:11500  task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 ksys_sync+0x94/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f12e238eba9
RSP: 002b:00007f12e05d5038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f12e25d6090 RCX: 00007f12e238eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f12e25d6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f12e25d6128 R14: 00007f12e25d6090 R15: 00007ffe404fb898
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kswapd0/86:
2 locks held by getty/5674:
 #0: ffff8880227da0a0 (&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/u8:3/5879:
 #0: ffff8880215d1148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000365fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f539f48 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0
2 locks held by syz-executor/8845:
3 locks held by kworker/1:10/10685:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000382fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88812062f240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180
1 lock held by syz.9.682/11979:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.7.698/12060:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.1.746/12650:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.4.781/12867:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.8.782/12872:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.0.791/13039:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.6.819/13495:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.2.833/13577:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.5.836/13597:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.5.836/13598:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.9.857/13688:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.7.866/13749:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.3.905/13844:
 #0: ffff8881279a80e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz-executor/13881:
 #0: ffffffff8e13fb78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
9 locks held by syz-executor/13976:
 #0: ffff888020af2428 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x211/0xb30
 #1: ffff88803eafe488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540
 #2: ffff888022a35788 (kn->active#48){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540
 #3: ffffffff8edb0188 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360
 #4: ffff888033c580e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x800
 #5: ffff88811025a250 (&devlink->lock_key#23){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160
 #6: ffffffff8f539f48 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xe5/0x670
 #7: ffff888027228d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0xdf5/0x1ff0
 #8: ffffffff8e13fb78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730

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

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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 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: 13985 Comm: syz.4.923 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+0x332/0xd20
Code: e5 15 09 d5 09 cd 44 09 f5 41 89 6c c7 20 45 89 44 c7 24 4c 89 7c 24 10 4d 8d 34 c7 81 e5 ff 1f 00 00 48 0f a3 2d 3e ff 0a 12 <73> 10 48 69 c5 c8 00 00 00 48 8d 80 10 73 49 93 eb 40 83 3d a5 8e
RSP: 0018:ffffc9000476f408 EFLAGS: 00000003
RAX: 0000000000000000 RBX: ffffffff8e13a0e0 RCX: 0000000000000007
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888060ae1cc0
RBP: 0000000000000007 R08: 0000000000000000 R09: ffffffff8172d195
R10: ffffc9000476f658 R11: ffffffff81ac4b00 R12: 0000000000020000
R13: 0000000000000000 R14: ffff888060ae27b0 R15: ffff888060ae27b0
FS:  0000555577d5a500(0000) GS:ffff8880b8615000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe7599e7000 CR3: 0000000112b44000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x120/0x360
 unwind_next_frame+0xc2/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 save_stack+0xf5/0x1f0
 __reset_page_owner+0x71/0x1f0
 __free_frozen_pages+0xbc4/0xd30
 vfree+0x25a/0x400
 kcov_close+0x28/0x50
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe763b8eba9
Code: Unable to access opcode bytes at 0x7fe763b8eb7f.
RSP: 002b:00007fff436cdaf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffdfc RBX: 000000000007ba07 RCX: 00007fe763b8eba9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe763dd5fac
RBP: 0000000000000fd2 R08: 7fffffffffffffff R09: 00000001436cddef
R10: 00007fff436cdbf0 R11: 0000000000000246 R12: 00007fe763dd5fac
R13: 00007fff436cdbf0 R14: 000000000007c9d9 R15: 00007fff436cdc10
 </TASK>
