INFO: task kworker/u4:1:12 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:1    state:D stack:22488 pid:12    ppid:2      flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
 hfsplus_find_init+0x154/0x1d0 fs/hfsplus/bfind.c:28
 hfsplus_cat_write_inode+0x1e7/0x7b0 fs/hfsplus/inode.c:593
 write_inode fs/fs-writeback.c:1483 [inline]
 __writeback_single_inode+0x705/0xee0 fs/fs-writeback.c:1700
 writeback_sb_inodes+0x77c/0xef0 fs/fs-writeback.c:1926
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:1997
 wb_writeback+0x464/0xba0 fs/fs-writeback.c:2107
 wb_check_background_flush fs/fs-writeback.c:2177 [inline]
 wb_do_writeback fs/fs-writeback.c:2265 [inline]
 wb_workfn+0xb32/0xe20 fs/fs-writeback.c:2292
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u4:1/12:
 #0: ffff88814005cd38 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff88814005cd38 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90000117d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90000117d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffff88807b3420e0
 (
&type->s_umount_key
#66
){++++}-{3:3}
, at: super_trylock_shared+0x20/0xf0 fs/super.c:607
 #3: 
ffff88802f4f60b0
 (
&tree->tree_lock
){+.+.}-{3:3}
, at: hfsplus_find_init+0x154/0x1d0 fs/hfsplus/bfind.c:28
2 locks held by kworker/1:0/23:
 #0: 
ffff888017872538
 (
(wq_completion)rcu_gp
){+.+.}-{0:0}
, at: process_one_work kernel/workqueue.c:2609 [inline]
, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: 
ffffc900001d7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
ffffc900001d7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
1 lock held by khungtaskd/29:
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
5 locks held by kworker/u4:3/49:
 #0: ffff888017873938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017873938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: 
ffffc90000ba7d00
 (
net_cleanup_work
){+.+.}-{0:0}
, at: process_one_work kernel/workqueue.c:2609 [inline]
, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: 
ffffffff8dfa8610
 (
pernet_ops_rwsem
){++++}-{3:3}
, at: cleanup_net+0x136/0xb90 net/core/net_namespace.c:606
 #3: 
ffffffff8dfb5448
 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0xe9/0xa60 net/core/dev.c:11606
 #4: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
 #4: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x448/0x830 kernel/rcu/tree_exp.h:1004
3 locks held by kworker/u4:5/79:
 #0: ffff88802be9bd38 (
(wq_completion)ipv6_addrconf
){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc900015f7d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc900015f7d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x14e0 net/ipv6/addrconf.c:4158
3 locks held by kworker/u4:6/146:
 #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90002d37d00 ((linkwatch_work).work){+.+.}-{0:0}
, at: process_one_work kernel/workqueue.c:2609 [inline]
, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8dfb5448
 (
rtnl_mutex
){+.+.}-{3:3}
, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:286
3 locks held by kworker/0:2/789:
 #0: 
ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90003b17d00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90003b17d00 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8dfb5448
 (
rtnl_mutex
){+.+.}-{3:3}
, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
2 locks held by dhcpcd/5432:
 #0: ffff8880304bb690 (nlk_cb_mutex-ROUTE){+.+.}-{3:3}
, at: __netlink_dump_start+0xf4/0x810 net/netlink/af_netlink.c:2336
 #1: 
ffffffff8dfb5448
 (
rtnl_mutex
){+.+.}-{3:3}
, at: netlink_dump+0x71f/0xde0 net/netlink/af_netlink.c:2263
2 locks held by getty/5526:
 #0: ffff88814cbc10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000327e2f0 (
&ldata->atomic_read_lock
){+.+.}-{3:3}
, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
3 locks held by kworker/1:5/5856:
 #0: ffff888017871d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017871d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90004c2fd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90004c2fd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x91/0xd70 net/wireless/reg.c:2463
7 locks held by syz.0.134/6456:
1 lock held by syz-executor/7112:
 #0: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
 #0: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6469
1 lock held by syz-executor/7115:
 #0: ffffffff8dfb5448
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6469
1 lock held by syz-executor/7120:
 #0: 
ffffffff8dfb5448
 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6469
1 lock held by syz-executor/7121:
 #0: 
ffffffff8dfb5448
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6469

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

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf41/0xf80 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 6456 Comm: syz.0.134 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:424
Code: fa e8 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 ac 68 40 fd 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 44 89 f9 80 e1 07 38 c1 7c aa 4c 89 ff
RSP: 0018:ffffc90010226bb0 EFLAGS: 00000002
RAX: 0000000000000032 RBX: 0000000000000032 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: ffff888020db0237 R09: 1ffff110041b6046
R10: dffffc0000000000 R11: ffffed10041b6047 R12: dffffc0000000000
R13: ffffffff96edb8e4 R14: ffffffff971c4240 R15: 0000000000000000
FS:  00007f388c4a26c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd43a917d60 CR3: 000000002cf74000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 serial_out drivers/tty/serial/8250/8250.h:122 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
 serial8250_console_write+0x10fd/0x17a0 drivers/tty/serial/8250/8250_port.c:3474
 console_emit_next_record kernel/printk/printk.c:2944 [inline]
 console_flush_all+0x6cd/0xd00 kernel/printk/printk.c:3000
 console_unlock+0xae/0x340 kernel/printk/printk.c:3069
 vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341
 _printk+0xd0/0x110 kernel/printk/printk.c:2366
 hfsplus_bnode_read_u16 fs/hfsplus/bnode.c:60 [inline]
 hfsplus_bnode_dump+0x321/0x440 fs/hfsplus/bnode.c:362
 hfsplus_brec_remove+0x47a/0x550 fs/hfsplus/brec.c:229
 __hfsplus_delete_attr+0x1d5/0x360 fs/hfsplus/attributes.c:299
 hfsplus_delete_attr+0x232/0x2d0 fs/hfsplus/attributes.c:345
 __hfsplus_setxattr+0x48a/0x1f00 fs/hfsplus/xattr.c:346
 hfsplus_setxattr+0x11e/0x170 fs/hfsplus/xattr.c:438
 hfsplus_trusted_setxattr+0x40/0x50 fs/hfsplus/xattr_trusted.c:30
 __vfs_setxattr+0x431/0x470 fs/xattr.c:201
 __vfs_setxattr_noperm+0x12d/0x5e0 fs/xattr.c:235
 vfs_setxattr+0x16c/0x2f0 fs/xattr.c:322
 do_setxattr fs/xattr.c:630 [inline]
 path_setxattr+0x362/0x550 fs/xattr.c:659
 __do_sys_lsetxattr fs/xattr.c:684 [inline]
 __se_sys_lsetxattr fs/xattr.c:680 [inline]
 __x64_sys_lsetxattr+0xb8/0xd0 fs/xattr.c:680
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f388b58f749
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:00007f388c4a2038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007f388b7e5fa0 RCX: 00007f388b58f749
RDX: 00002000000001c0 RSI: 0000200000000180 RDI: 00002000000001c0
RBP: 00007f388b613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000361 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f388b7e6038 R14: 00007f388b7e5fa0 R15: 00007ffd5e316708
 </TASK>