INFO: task kworker/u9:1:32 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u9:1    state:D stack:22680 pid:32    tgid:32    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:6)
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x883/0x1080
 down_write+0x1bc/0x200
 f2fs_issue_checkpoint+0x437/0x790
 f2fs_balance_fs_bg+0x576/0x990
 f2fs_write_node_pages+0x158/0x700
 do_writepages+0x32e/0x550
 __writeback_single_inode+0x133/0x10e0
 writeback_sb_inodes+0x979/0x19d0
 __writeback_inodes_wb+0x111/0x240
 wb_writeback+0x459/0xb00
 wb_workfn+0xb12/0xf10
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u9:1/32:
 #0: ffff888162687940 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc90000a77c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffff8881b08360d8 (&type->s_umount_key#64){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0
 #3: ffff8881b0ab54b8 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x437/0x790
1 lock held by khungtaskd/34:
 #0: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5636:
 #0: ffff888110b290a0 (&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
1 lock held by syz-executor/8705:
3 locks held by syz.6.731/12287:
1 lock held by syz.3.1241/16706:
2 locks held by dhcpcd/16715:
 #0: ffff8881128b0260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xe10
 #1: ffffffff8e963328 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
1 lock held by dhcpcd/16719:
 #0: ffff888115f62260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xe10

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

NMI backtrace for cpu 0
CPU: 0 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+0xfaa/0x1000
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 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: 97 Comm: kworker/1:1H 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:  0x0 (xfs-log/loop3)
RIP: 0010:dequeue_entities+0x880/0x3aa0
Code: ff e8 84 c3 99 00 49 8b 1f 4c 89 e8 48 c1 e8 03 48 89 84 24 c0 00 00 00 80 3c 28 00 74 08 4c 89 ef e8 64 c3 99 00 49 29 5d 00 <49> 8d 5d 08 48 89 d8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 55 06 00
RSP: 0018:ffffc90002817938 EFLAGS: 00000006
RAX: 1ffff110478c75e0 RBX: 00000000056ae400 RCX: dffffc0000000000
RDX: 000000000131ac00 RSI: ffff888169593b80 RDI: ffff88823c63af20
RBP: dffffc0000000000 R08: ffffffff903215b7 R09: 1ffffffff20642b6
R10: dffffc0000000000 R11: fffffbfff20642b7 R12: 0000000000000009
R13: ffff88823c63af00 R14: ffff888169593c38 R15: ffff888169593b80
FS:  0000000000000000(0000) GS:ffff8882a9245000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd3a35b9ff8 CR3: 000000016a31e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 dequeue_task_fair+0x200/0x660
 __schedule+0x6dc/0x5680
 schedule+0x164/0x360
 worker_thread+0xc21/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
