INFO: task kworker/u4:6:3648 blocked for more than 143 seconds.
      Not tainted 5.15.167-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:6    state:D stack:21048 pid: 3648 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6515
 __mutex_lock_common+0xe34/0x25a0 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 jfs_commit_inode+0x242/0x580 fs/jfs/inode.c:102
 jfs_write_inode+0x13f/0x210 fs/jfs/inode.c:132
 write_inode fs/fs-writeback.c:1495 [inline]
 __writeback_single_inode+0x644/0xe30 fs/fs-writeback.c:1705
 writeback_sb_inodes+0xbce/0x1a40 fs/fs-writeback.c:1930
 __writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:2001
 wb_writeback+0x465/0xc50 fs/fs-writeback.c:2106
 wb_check_background_flush fs/fs-writeback.c:2172 [inline]
 wb_do_writeback fs/fs-writeback.c:2260 [inline]
 wb_workfn+0xd07/0x1130 fs/fs-writeback.c:2288
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:1/144:
2 locks held by getty/3326:
 #0: ffff88814b2ff098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002b9e2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
4 locks held by kworker/u4:6/3648:
 #0: ffff8881407fc938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc9000115fd20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffff8880631640e0 (&type->s_umount_key#79){++++}-{3:3}, at: trylock_super+0x1b/0xf0 fs/super.c:418
 #3: ffff88806118d508 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x242/0x580 fs/jfs/inode.c:102
3 locks held by kworker/u4:7/3652:
3 locks held by udevd/3666:
3 locks held by kworker/0:9/3676:
 #0: ffff888017070938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90003027d20 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffff888062df1240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x2cd/0x4120 drivers/net/netdevsim/fib.c:1478
4 locks held by syz.0.394/5270:
2 locks held by syz.2.452/5602:
 #0: ffff8880631640e0 (&type->s_umount_key#79){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
 #1: ffff88802043a7d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff88802043a7d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768
1 lock held by syz.0.710/6855:
 #0: ffff8880631640e0 (&type->s_umount_key#79){++++}-{3:3}, at: user_get_super+0xd3/0x250 fs/super.c:846
3 locks held by syz-executor/6947:
3 locks held by kworker/1:20/7077:
1 lock held by syz.1.900/7837:
1 lock held by syz.0.904/7856:

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7856 Comm: syz.0.904 Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:___sys_recvmsg+0x4fe/0x690 net/socket.c:2695
Code: 35 2b 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 a0 01 00 00 0f 85 92 01 00 00 44 89 f8 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f <5d> c3 e8 9b 4c 3e f9 48 8b 04 24 48 8d 58 58 48 89 d8 48 c1 e8 03
RSP: 0018:ffffc90004067c70 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 1ffff9200080cf2c
RDX: ffffc9000ee01000 RSI: ffffffff8ad904a0 RDI: ffffffff8ad90460
RBP: ffffc90004067c70 R08: ffffffff88420560 R09: fffff5200080ced9
R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000203841c0
R13: 000000000000e104 R14: dffffc0000000000 R15: 00000000200000c0
FS:  00007f24ce9026c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d41eff8 CR3: 00000000688c1000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 do_recvmmsg+0x36f/0x8f0 net/socket.c:2786
 __sys_recvmmsg net/socket.c:2865 [inline]
 __do_sys_recvmmsg net/socket.c:2888 [inline]
 __se_sys_recvmmsg net/socket.c:2881 [inline]
 __x64_sys_recvmmsg+0x195/0x240 net/socket.c:2881
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f24d04aaff9
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:00007f24ce902038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f24d0663058 RCX: 00007f24d04aaff9
RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000008
RBP: 00007f24d051d296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f24d0663058 R15: 00007ffd830770c8
 </TASK>