INFO: task kworker/u10:4:1090 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u10:4   state:D stack:23048 pid:1090  tgid:1090  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:2)
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 jfs_commit_inode+0x1ca/0x530
 jfs_write_inode+0x145/0x220
 __writeback_single_inode+0x6f1/0xff0
 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>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
4 locks held by kworker/u10:4/1090:
 #0: ffff888100194948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90007077bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888108e400e0 (&type->s_umount_key#80){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0
 #3: ffff888118132fe0 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530
2 locks held by getty/5678:
 #0: ffff88801f0fd0a0 (&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
4 locks held by syz.2.80/6562:
1 lock held by syz-executor/7409:
2 locks held by syz.6.606/9501:

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

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: 9501 Comm: syz.6.606 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:look_up_lock_class+0x6f/0x170
Code: 24 00 02 00 00 0f 85 c0 00 00 00 89 f0 49 01 c7 48 b8 eb 83 b5 80 46 86 c8 61 49 0f af c7 48 c1 e8 34 48 8b 1c c5 f0 47 29 96 <e8> dc 01 00 00 48 85 db 0f 84 c0 00 00 00 4c 39 7b 40 74 05 48 8b
RSP: 0018:ffffc900001e09e8 EFLAGS: 00000007
RAX: 000000000000046c RBX: ffffffff9349ea40 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900001e0be0
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: ffffc900001e0be8 R11: fffff5200003c17f R12: 0000000000000000
R13: ffffc900001e0be0 R14: ffffc900001e0be0 R15: ffffffff99b01340
FS:  00007fe39f0e96c0(0000) GS:ffff8881a3c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe393fffe00 CR3: 0000000040b1e000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 register_lock_class+0x51/0x320
 __lock_acquire+0x99/0xd20
 lock_acquire+0x120/0x360
 call_timer_fn+0xdb/0x5f0
 __run_timer_base+0x61a/0x860
 run_timer_softirq+0xb7/0x180
 handle_softirqs+0x286/0x870
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:vprintk_emit+0x58f/0x7a0
Code: 85 32 01 00 00 e8 11 87 1f 00 41 89 df 4d 85 f6 48 8b 1c 24 75 07 e8 00 87 1f 00 eb 06 e8 f9 86 1f 00 fb 48 c7 c7 c0 e1 12 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 b9 35
RSP: 0018:ffffc90003426da0 EFLAGS: 00000287
RAX: ffffffff81a02717 RBX: ffffffff81a025d4 RCX: 0000000000080000
RDX: ffffc9002af2b000 RSI: 000000000005d7a2 RDI: ffffffff8e12e1c0
RBP: ffffc90003426eb0 R08: ffffffff8fa39037 R09: 1ffffffff1f47206
R10: dffffc0000000000 R11: fffffbfff1f47207 R12: dffffc0000000000
R13: 1ffff92000684db8 R14: 0000000000000200 R15: 000000000000002e
 _printk+0xcf/0x120
 set_capacity_and_notify+0x208/0x2d0
 loop_set_size+0x44/0xb0
 loop_configure+0x9f4/0xe50
 lo_ioctl+0x810/0x1c10
 blkdev_ioctl+0x5a8/0x6d0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe39e18e7eb
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007fe39f0e8dc0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fe39e18e7eb
RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000001f6e7
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007fe39f0e8ef0 R14: 00007fe39f0e8eb0 R15: 00007fe393e00000
 </TASK>
