INFO: task kworker/u9:4:1090 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u9:4    state:D stack:20896 pid:1090  tgid:1090  ppid:2      task_flags:0x4208160 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:7)
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x872/0xfe0
 down_write+0x1ab/0x1f0
 f2fs_issue_checkpoint+0x39c/0x570
 f2fs_balance_fs_bg+0x54d/0x980
 f2fs_write_node_pages+0x146/0x6e0
 do_writepages+0x32e/0x550
 __writeback_single_inode+0x145/0xff0
 writeback_sb_inodes+0x6c7/0x1010
 __writeback_inodes_wb+0x111/0x240
 wb_writeback+0x44f/0xaf0
 wb_workfn+0xaef/0xef0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
INFO: lockdep is turned off.
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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 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: 15587 Comm: syz.7.2096 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_release+0x9/0x3e0
Code: 24 e9 08 fa ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 57 41 56 <41> 55 41 54 53 48 83 ec 30 49 89 f5 49 89 fe 65 48 8b 05 70 e4 02
RSP: 0018:ffffc900025ff2e8 EFLAGS: 00000282
RAX: ffffffff823b7b01 RBX: ffff88802d596c20 RCX: ffffffff823b7c0a
RDX: 0000000000000001 RSI: ffffffff823b7c19 RDI: ffff88802d596c38
RBP: 0000000000000000 R08: ffff88802d596da3 R09: 1ffff11005ab2db4
R10: dffffc0000000000 R11: ffffed1005ab2db5 R12: ffff8881292b8084
R13: ffff888028a29250 R14: ffff88802d596c20 R15: ffff88802d596c70
FS:  00007f2ad20ce6c0(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffd CR3: 000000002fb12000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 _raw_spin_unlock+0x16/0x50
 igrab+0x89/0xb0
 f2fs_write_checkpoint+0xaea/0x1df0
 f2fs_issue_checkpoint+0x3ac/0x570
 f2fs_do_sync_file+0x869/0x1860
 f2fs_file_write_iter+0x753/0x2410
 vfs_write+0x5c9/0xb30
 __x64_sys_pwrite64+0x193/0x220
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2ad118ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2ad20ce038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f2ad13b5fa0 RCX: 00007f2ad118ebe9
RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000005
RBP: 00007f2ad1211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000fecc R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2ad13b6038 R14: 00007f2ad13b5fa0 R15: 00007ffc19b0a568
 </TASK>
