INFO: task kworker/u4:2:154 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:2    state:D
 stack:22528 pid:  154 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn
 (flush-7:0)

Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 hfs_find_init+0x15b/0x1d0 fs/hfs/bfind.c:-1
 hfs_write_inode+0x349/0x970 fs/hfs/inode.c:458
 write_inode fs/fs-writeback.c:1495 [inline]
 __writeback_single_inode+0x6c3/0xda0 fs/fs-writeback.c:1705
 writeback_sb_inodes+0x9fe/0x1610 fs/fs-writeback.c:1930
 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2001
 wb_writeback+0x455/0xb90 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+0xb47/0xe60 fs/fs-writeback.c:2288
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 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: 
ffffffff8c11c460
 (
rcu_read_lock
){....}-{1:2}
, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:2/154:
 #0: 
ffff8881421d0938
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: 
ffffc90002017d00
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88802ac180e0 (&type->s_umount_key#84){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff8880778220b0 (&tree->tree_lock#2){+.+.}-{3:3}, at: hfs_find_init+0x15b/0x1d0 fs/hfs/bfind.c:-1
1 lock held by dhcpcd/3853:
 #0: ffffffff8d237b88 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d237b88 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
2 locks held by getty/3946:
 #0: ffff88802c2e2098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
3 locks held by kworker/u4:12/4589:
 #0: ffff888016879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: 
ffffc90003d97d00
 (
(linkwatch_work).work
){+.+.}-{0:0}
, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: 
ffffffff8d237b88
 (
rtnl_mutex
){+.+.}-{3:3}
, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
2 locks held by kworker/1:9/4667:
 #0: 
ffff888016870938
 (
(wq_completion)events
){+.+.}-{0:0}
, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: 
ffffc90003da7d00
 (
(work_completion)(&pwq->unbound_release_work)
){+.+.}-{0:0}
, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
3 locks held by kworker/1:12/4670:
 #0: 
ffff888016870938
 (
(wq_completion)events
){+.+.}-{0:0}
, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: 
ffffc90003f0fd00
 (
(work_completion)(&pwq->unbound_release_work)
){+.+.}-{0:0}
, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: 
ffffffff8c120ee8
 (
rcu_state.exp_mutex
){+.+.}-{3:3}
, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
, at: synchronize_rcu_expedited+0x320/0x6b0 kernel/rcu/tree_exp.h:845
2 locks held by kworker/1:14/4672:
 #0: 
ffff888016872138
 (
(wq_completion)rcu_gp
){+.+.}-{0:0}
, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: 
ffffc90003f2fd00
 (
(work_completion)(&rew.rew_work)
){+.+.}-{0:0}
, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/1:16/4675:
 #0: 
ffff888016870938
 (
(wq_completion)events
){+.+.}-{0:0}
, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: 
ffffc90003f4fd00
 (
free_ipc_work
){+.+.}-{0:0}
, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
6 locks held by syz.0.171/4834:
1 lock held by syz-executor/5319:
 #0: 
ffffffff8c120ee8
 (
rcu_state.exp_mutex
){+.+.}-{3:3}
, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
, at: synchronize_rcu_expedited+0x320/0x6b0 kernel/rcu/tree_exp.h:845
3 locks held by syz-executor/5322:
 #0: 
ffff8880523dcff0
 (
&hdev->req_lock
){+.+.}-{3:3}
, at: hci_dev_do_close+0x5f/0x1030 net/bluetooth/hci_core.c:1737
 #1: 
ffff8880523dc078
 (
&hdev->lock
){+.+.}-{3:3}
, at: hci_dev_do_close+0x3f4/0x1030 net/bluetooth/hci_core.c:1782
 #2: 
ffffffff8d37dfe8
 (
hci_cb_list_lock
){+.+.}-{3:3}
, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1517 [inline]
, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622
5 locks held by kworker/0:17/6672:
 #0: 
ffff8880b903a318
 (
&rq->__lock
){-.-.}-{2:2}
, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
 #1: 
ffffc900032bfd00
 (
(work_completion)(&(&hdev->cmd_timer)->work)
){+.+.}-{0:0}
, at: psi_task_switch+0x4d6/0x810 kernel/sched/psi.c:891
 #2: 
ffff88805bdd8ee0
 (
&r->consumer_lock
#2
){+.+.}-{2:2}
, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
, at: ptr_ring_consume_bh include/linux/ptr_ring.h:365 [inline]
, at: wg_packet_decrypt_worker+0x8ed/0xda0 drivers/net/wireguard/receive.c:506
 #3: 
ffff8880b913a318
 (
&rq->__lock
){-.-.}-{2:2}
, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946
 #4: 
ffffffff962c1cc8
 (
&obj_hash[i].lock
){-.-.}-{2:2}
, at: debug_object_activate+0x65/0x480 lib/debugobjects.c:694
1 lock held by syz.8.613/7100:
 #0: 
ffffffff8c7e20a8
 (
tty_mutex
){+.+.}-{3:3}
, at: tty_release_struct+0xaa/0xd0 drivers/tty/tty_io.c:1718
3 locks held by syz.0.617/7104:
 #0: 
ffff888063884ff0
 (
&hdev->req_lock
){+.+.}-{3:3}
, at: hci_dev_do_close+0x5f/0x1030 net/bluetooth/hci_core.c:1737
 #1: 
ffff888063884078
 (
&hdev->lock
){+.+.}-{3:3}, at: hci_dev_do_close+0x3f4/0x1030 net/bluetooth/hci_core.c:1782
 #2: 
ffffffff8d37dfe8
 (
hci_cb_list_lock
){+.+.}-{3:3}
, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1517 [inline]
, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622
1 lock held by syz-executor/7358:
 #0: 
ffffffff8d237b88
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
2 locks held by syz-executor/7360:
 #0: 
ffffffff8d22bf10
 (
pernet_ops_rwsem
){++++}-{3:3}
, at: copy_net_ns+0x32e/0x5b0 net/core/net_namespace.c:499
 #1: 
ffffffff8d237b88
 (
rtnl_mutex
){+.+.}-{3:3}
, at: wg_netns_pre_exit+0x18/0x1c0 drivers/net/wireguard/device.c:405
1 lock held by syz-executor/7361:
 #0: 
ffffffff8d237b88
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
2 locks held by syz-executor/7369:
 #0: 
ffffffff8d22bf10
 (
pernet_ops_rwsem
){++++}-{3:3}
, at: copy_net_ns+0x32e/0x5b0 net/core/net_namespace.c:499
 #1: 
ffffffff8d237b88
 (
rtnl_mutex
){+.+.}-{3:3}
, at: register_nexthop_notifier+0x7d/0x210 net/ipv4/nexthop.c:3607
2 locks held by syz-executor/7372:
 #0: 
ffffffff8d22bf10
 (
pernet_ops_rwsem
){++++}-{3:3}
, at: copy_net_ns+0x32e/0x5b0 net/core/net_namespace.c:499
 #1: ffffffff8d237b88
 (
rtnl_mutex
){+.+.}-{3:3}
, at: ip_tunnel_init_net+0x224/0x6b0 net/ipv4/ip_tunnel.c:1097

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6674 Comm: kworker/0:18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events hci_cmd_timeout
RIP: 0010:format_decode+0x283/0x1330 lib/vsprintf.c:-1
Code: 00 00 02 00 00 00 eb 19 e8 4a f3 79 fd 49 bf 00 00 00 00 04 00 00 00 eb 08 e8 39 f3 79 fd 49 89 ef 48 8b 44 24 10 0f b6 04 18 <84> c0 75 3a 48 8b 44 24 18 0f b6 04 18 84 c0 75 48 48 8b 04 24 4c
RSP: 0018:ffffc900031ef450 EFLAGS: 00000293
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88807c18d940
RDX: 0000000000000000 RSI: ffffffff8c73af40 RDI: 0000000000000030
RBP: 0000001000000000 R08: ffff88807c18d940 R09: 0000000000000005
R10: 0000000000000030 R11: 0000000000000000 R12: ffffffff8a0bcc27
R13: 1ffffffff1417984 R14: ffffffff8a0bcc27 R15: 0000001000000000
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055bfa9b5b950 CR3: 0000000059627000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 vsnprintf+0xef/0x1a00 lib/vsprintf.c:2763
 sprintf+0xd6/0x120 lib/vsprintf.c:3013
 print_time kernel/printk/printk.c:1274 [inline]
 info_print_prefix+0x152/0x300 kernel/printk/printk.c:1300
 record_print_text kernel/printk/printk.c:1349 [inline]
 console_unlock+0x7f5/0x1200 kernel/printk/printk.c:2725
 vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
 _printk+0xcc/0x110 kernel/printk/printk.c:2299
 bt_err+0x108/0x150 net/bluetooth/lib.c:180
 hci_cmd_timeout+0x10a/0x220 net/bluetooth/hci_core.c:2779
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>