INFO: task kworker/u4:4:1449 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:4    state:D stack:23888 pid: 1449 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 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+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
 hfsplus_cat_write_inode+0x210/0x8d0 fs/hfsplus/inode.c:613
 write_inode fs/fs-writeback.c:1505 [inline]
 __writeback_single_inode+0x6c4/0xda0 fs/fs-writeback.c:1715
 writeback_sb_inodes+0xaaa/0x1750 fs/fs-writeback.c:1940
 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
 wb_writeback+0x45e/0xbc0 fs/fs-writeback.c:2116
 wb_check_background_flush fs/fs-writeback.c:2182 [inline]
 wb_do_writeback fs/fs-writeback.c:2270 [inline]
 wb_workfn+0xbd6/0xf20 fs/fs-writeback.c:2298
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/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:
4 locks held by kworker/u4:0/9:
 #0: 
ffff8880199c0138
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: 
ffffc90000ce7d00
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}
, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: 
ffff8880204240e0
 (
&type->s_umount_key
#54
){.+.+}-{3:3}
, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: 
ffff88807de4c0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
1 lock held by khungtaskd/27:
 #0: 
ffffffff8c31ef20
 (
rcu_read_lock
){....}-{1:2}
, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:2/154:
 #0: 
ffff8880199c0138
 (
(wq_completion)writeback
){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: 
ffffc90001ca7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff88807616e0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807616a0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
4 locks held by kworker/u4:3/155:
 #0: 
ffff8880199c0138
 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90001cb7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff88814c4660e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807433a0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
4 locks held by kworker/u4:4/1449:
 #0: ffff8880199c0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: 
ffffc900053f7d00
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: 
ffff888020c3c0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff888020c3e0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
2 locks held by getty/3944:
 #0: ffff88802c896098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
4 locks held by kworker/u4:5/4486:
 #0: ffff8880199c0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90002d1fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff8880784420e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff8880792be0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
6 locks held by syz.0.17/5215:
6 locks held by syz.1.18/5232:
6 locks held by syz.2.19/5254:
6 locks held by syz.3.20/5275:
6 locks held by syz.4.21/5300:
4 locks held by kworker/u4:9/5318:
 #0: 
ffff8880199c0138
 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000346fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff88807c1e80e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff8880581ce0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
6 locks held by syz.5.22/5331:
1 lock held by syz-executor/5333:

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 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+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 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: 5275 Comm: syz.3.20 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__sanitizer_cov_trace_switch+0xd6/0xe0 kernel/kcov.c:-1
Code: e6 05 4d 8d 66 28 4d 39 fc 77 9d 4b 89 4c 33 08 4f 89 54 33 10 4b 89 7c 33 18 4b 89 54 33 20 48 ff c3 49 89 1b eb 81 5b 41 5c <41> 5e 41 5f c3 0f 1f 44 00 00 c7 87 10 16 00 00 00 00 00 00 48 c7
RSP: 0018:ffffc9000330f078 EFLAGS: 00000246
RAX: 0000000000000002 RBX: dffffc0000000000 RCX: 0000000000000001
RDX: ffffffff8405f939 RSI: ffffffff8c93dd40 RDI: 0000000000000003
RBP: ffffffff8a2be282 R08: ffff888019ff8000 R09: 0000000000000002
R10: 0000000000000002 R11: 0000000000000000 R12: ffffffff8a2be282
R13: ffff0a00fffffd03 R14: 1ffff92000661e2b R15: 0000000000000003
FS:  00007f920032b6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f461f196436 CR3: 000000005a27e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 format_decode+0x89/0x1330 lib/vsprintf.c:2524
 vsnprintf+0xef/0x1c20 lib/vsprintf.c:2763
 snprintf+0xe5/0x140 lib/vsprintf.c:2944
 print_caller kernel/printk/printk.c:1283 [inline]
 info_print_prefix+0x1fa/0x360 kernel/printk/printk.c:1302
 record_print_text kernel/printk/printk.c:1349 [inline]
 console_unlock+0x650/0x10f0 kernel/printk/printk.c:2725
 vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
 _printk+0xda/0x130 kernel/printk/printk.c:2299
 hfsplus_bnode_read_u16 fs/hfsplus/bnode.c:62 [inline]
 hfsplus_bnode_dump+0x39c/0x4d0 fs/hfsplus/bnode.c:369
 hfsplus_brec_remove+0x476/0x540 fs/hfsplus/brec.c:229
 __hfsplus_delete_attr+0x1db/0x380 fs/hfsplus/attributes.c:299
 hfsplus_delete_all_attrs+0x262/0x3b0 fs/hfsplus/attributes.c:378
 hfsplus_delete_cat+0x96e/0xdb0 fs/hfsplus/catalog.c:425
 hfsplus_unlink+0x395/0x800 fs/hfsplus/dir.c:385
 vfs_unlink+0x376/0x600 fs/namei.c:4288
 do_unlinkat+0x391/0x710 fs/namei.c:4356
 __do_sys_unlinkat fs/namei.c:4399 [inline]
 __se_sys_unlinkat fs/namei.c:4392 [inline]
 __x64_sys_unlinkat+0xd1/0xe0 fs/namei.c:4392
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9200cc7ef9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f920032b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007f9200f32fa0 RCX: 00007f9200cc7ef9
RDX: 0000000000000000 RSI: 0000200000000380 RDI: ffffffffffffff9c
RBP: 00007f9200d5cee0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9200f33038 R14: 00007f9200f32fa0 R15: 00007ffe31a0c978
 </TASK>