INFO: task syz.0.211:7114 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.211       state:D stack:28800 pid:7114  tgid:7096  ppid:5807   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1585/0x5340
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x899/0x1040
 down_write_nested+0x1c6/0x210
 filename_create+0x200/0x370
 filename_mkdirat+0xd2/0x510
 __se_sys_mkdirat+0x35/0x150
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f63cbb9b607
RSP: 002b:00007f63ccaece58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f63ccaecee0 RCX: 00007f63cbb9b607
RDX: 00000000000001ff RSI: 00002000000000c0 RDI: 00000000ffffff9c
RBP: 0000200000000080 R08: 0000200000000140 R09: 0000000000000000
R10: 0000200000000080 R11: 0000000000000246 R12: 00002000000000c0
R13: 00007f63ccaecea0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
6 locks held by kworker/u8:1/13:
1 lock held by khungtaskd/35:
 #0: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
4 locks held by kworker/u9:6/1094:
 #0: ffff8881626de948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830
 #1: ffffc900075bfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830
 #2: ffff88801fcd00e0 (&type->s_umount_key#65){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0
 #3: ffff888115c501c8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530
2 locks held by getty/5631:
 #0: ffff88816f0570a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
4 locks held by syz.0.211/7097:
2 locks held by syz.0.211/7114:
 #0: ffff88801fcd0420 (sb_writers#26){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
 #1: ffff888115c50578 (&type->i_mutex_dir_key#15/1){+.+.}-{4:4}, at: filename_create+0x200/0x370
3 locks held by kworker/1:7/8177:
 #0: ffff88810006b548 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830
 #1: ffffc900047e7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830
 #2: ffff8881a607c240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x202/0x3d0
2 locks held by syz.7.636/10770:
 #0: ffff88801fcd00e0 (&type->s_umount_key#65){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
 #1: ffff88810b1a0820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1c2/0xbd0
1 lock held by syz.1.740/11656:
 #0: ffffffff8e766578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
1 lock held by udevadm/11689:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 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+0xfd9/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 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: 13 Comm: kworker/u8:1 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
Workqueue: netns cleanup_net
RIP: 0010:deref_stack_reg+0x7/0x230
Code: e8 ee 10 b9 00 48 8b 4c 24 18 e9 f2 fe ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 41 55 <41> 54 53 48 83 ec 20 48 89 54 24 18 49 89 f0 49 89 ff 48 be 00 00
RSP: 0018:ffffc90000a088f0 EFLAGS: 00000287
RAX: fffffffffffffff0 RBX: ffffffff90a0143c RCX: 0000000000000000
RDX: ffffc90000a08a28 RSI: ffffc90000127760 RDI: ffffc90000a089e8
RBP: dffffc0000000000 R08: ffffc90000a08a47 R09: 0000000000000000
R10: ffffc90000a08a38 R11: fffff52000141149 R12: ffffc90000a08a38
R13: 1ffff9200014113f R14: ffffc90000a089e8 R15: 1ffffffff2140287
FS:  0000000000000000(0000) GS:ffff8882a946c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa643ae0440 CR3: 0000000198e1e000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 unwind_next_frame+0x18c6/0x23c0
 arch_stack_walk+0x11b/0x150
 stack_trace_save+0xa9/0x100
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 slab_free_after_rcu_debug+0x126/0x220
 rcu_core+0x7cd/0x1070
 handle_softirqs+0x22a/0x870
 __irq_exit_rcu+0x5f/0x150
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:vprintk_emit+0x45d/0x560
Code: 0f 84 44 ff ff ff e8 72 27 21 00 fb eb 44 e8 6a 27 21 00 e8 05 de 08 0a 4d 85 f6 74 94 e8 5b 27 21 00 fb 48 c7 c7 20 27 75 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 cb 16
RSP: 0018:ffffc90000127480 EFLAGS: 00000293
RAX: ffffffff81a46495 RBX: ffffffff81a4630f RCX: ffff888102afd700
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e752720
RBP: ffffc90000127530 R08: ffffffff901117b7 R09: 1ffffffff20222f6
R10: dffffc0000000000 R11: fffffbfff20222f7 R12: 0000000000000000
R13: 0000000000000025 R14: 0000000000000200 R15: 1ffff92000024e94
 _printk+0xdd/0x130
 netdev_info+0x11e/0x180
 __dev_set_promiscuity+0x2e7/0x710
 netif_set_promiscuity+0x50/0xe0
 dev_set_promiscuity+0x126/0x260
 del_nbp+0x12c/0xa60
 br_dev_delete+0x6e/0x110
 br_net_exit_rtnl+0xb1/0x120
 ops_undo_list+0x347/0x940
 cleanup_net+0x56b/0x800
 process_scheduled_works+0xb02/0x1830
 worker_thread+0xa50/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>
