INFO: task kworker/u8:3:49 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:3 state:D
stack:24544 pid:49 tgid:49 ppid:2 task_flags:0x4208160 flags:0x00080000
Workqueue: writeback wb_workfn
(flush-7:0)
Call Trace:
context_switch kernel/sched/core.c:5282 [inline]
__schedule+0x14db/0x5030 kernel/sched/core.c:6894
__schedule_loop kernel/sched/core.c:6976 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6991
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7048
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776
hfsplus_find_init+0x168/0x2d0 fs/hfsplus/bfind.c:28
hfsplus_cat_write_inode+0x1e6/0x7a0 fs/hfsplus/inode.c:625
write_inode fs/fs-writeback.c:1582 [inline]
__writeback_single_inode+0x75a/0x1070 fs/fs-writeback.c:1813
writeback_sb_inodes+0x93a/0x1870 fs/fs-writeback.c:2041
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2118
wb_writeback+0x43f/0xaa0 fs/fs-writeback.c:2229
wb_check_old_data_flush fs/fs-writeback.c:2333 [inline]
wb_do_writeback fs/fs-writeback.c:2386 [inline]
wb_workfn+0xad2/0xed0 fs/fs-writeback.c:2414
process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
process_scheduled_works kernel/workqueue.c:3362 [inline]
worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
kthread+0x389/0x480 kernel/kthread.c:467
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e144f60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e144f60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e144f60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:2/36:
#0:
ffff88801f2d9948
(
(wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc90000ac7c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffff88807c6cc0e0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff88807c6c80b0 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x168/0x2d0 fs/hfsplus/bfind.c:28
4 locks held by kworker/u8:3/49:
#0: ffff88801f2d9948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc90000ba7c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffff8880324680e0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff888031c7c0b0 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x168/0x2d0 fs/hfsplus/bfind.c:28
4 locks held by kworker/u8:6/78:
#0: ffff88801f2d9948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc9000259fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffff88805db1a0e0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff888071d4e0b0 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x168/0x2d0 fs/hfsplus/bfind.c:28
4 locks held by kworker/u8:9/1333:
#0: ffff88801f2d9948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc9000496fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffff88802f9e40e0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff88807b3d60b0 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x168/0x2d0 fs/hfsplus/bfind.c:28
4 locks held by kworker/u8:11/4349:
#0: ffff88801f2d9948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc9000d5cfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffff88807b0940e0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff8880790600b0 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x168/0x2d0 fs/hfsplus/bfind.c:28
4 locks held by kworker/u9:1/5144:
#0: ffff888058080948 ((wq_completion)hci3){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc9000e8f7c40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffff88802fc18ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1d3/0x400 net/bluetooth/hci_sync.c:331
#3: ffff88802fc180c0 (&hdev->lock){+.+.}-{4:4}, at: hci_abort_conn_sync+0x242/0xe30 net/bluetooth/hci_sync.c:5734
2 locks held by getty/5581:
#0: ffff88802fe0d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211
4 locks held by syz.0.17/6007:
4 locks held by syz.1.18/6029:
4 locks held by syz.2.19/6060:
3 locks held by kworker/u8:12/6073:
#0: ffff88813fe29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc90003037c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffffffff8f51bf48 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
4 locks held by syz.3.20/6088:
5 locks held by kworker/u8:18/6127:
11 locks held by syz.4.21/6129:
4 locks held by syz.5.22/6165:
3 locks held by syz-executor/6171:
#0: ffffffff8ec9ed08 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8ec9ed08 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8ec9ed08 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8f51bf48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8f51bf48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8f51bf48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8ec/0x1c90 net/core/rtnetlink.c:4071
#2: ffffffff8e14a578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#2: ffffffff8e14a578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x36e/0x6e0 kernel/rcu/tree_exp.h:961
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xf95/0xfe0 kernel/hung_task.c:515
kthread+0x389/0x480 kernel/kthread.c:467
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6165 Comm: syz.5.22 Not tainted syzkaller #0 PREEMPT(full)
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:407
Code: 29 a4 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 5c 0c 0b fd 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 c7 ca 44 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90003676d50 EFLAGS: 00000002
RAX: 0000000000000035 RBX: 0000000000000035 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: ffff888022388237 R09: 1ffff11004471046
R10: dffffc0000000000 R11: ffffffff851ce4d0 R12: dffffc0000000000
R13: ffffffff99b1ea0c R14: ffffffff99e331c0 R15: 0000000000000000
FS: 0000555564a0d500(0000) GS:ffff888125cf7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5c13317d60 CR3: 0000000076b94000 CR4: 00000000003526f0
Call Trace:
serial_port_out include/linux/serial_core.h:811 [inline]
serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3192 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
serial8250_console_write+0x13c5/0x1b60 drivers/tty/serial/8250/8250_port.c:3342
console_emit_next_record kernel/printk/printk.c:3131 [inline]
console_flush_one_record kernel/printk/printk.c:3217 [inline]
console_flush_all+0x713/0xb00 kernel/printk/printk.c:3291
__console_flush_and_unlock kernel/printk/printk.c:3321 [inline]
console_unlock+0xbb/0x190 kernel/printk/printk.c:3361
vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2428
_printk+0xcf/0x120 kernel/printk/printk.c:2453
hfsplus_bnode_read_u16 fs/hfsplus/bnode.c:60 [inline]
hfsplus_bnode_dump+0x16b/0xa00 fs/hfsplus/bnode.c:362
hfsplus_brec_remove+0x61c/0x700 fs/hfsplus/brec.c:229
__hfsplus_delete_attr+0x1d4/0x360 fs/hfsplus/attributes.c:299
hfsplus_delete_attr+0x239/0x3b0 fs/hfsplus/attributes.c:345
hfsplus_removexattr fs/hfsplus/xattr.c:794 [inline]
__hfsplus_setxattr+0x772/0x2170 fs/hfsplus/xattr.c:277
hfsplus_setxattr+0x11e/0x180 fs/hfsplus/xattr.c:434
hfsplus_trusted_setxattr+0x40/0x60 fs/hfsplus/xattr_trusted.c:30
__vfs_removexattr+0x431/0x470 fs/xattr.c:518
__vfs_removexattr_locked+0xe2/0x280 fs/xattr.c:553
vfs_removexattr+0x7f/0x230 fs/xattr.c:575
removexattr fs/xattr.c:1010 [inline]
filename_removexattr fs/xattr.c:1038 [inline]
path_removexattrat+0x360/0x6a0 fs/xattr.c:1071
__do_sys_lremovexattr fs/xattr.c:1089 [inline]
__se_sys_lremovexattr fs/xattr.c:1086 [inline]
__x64_sys_lremovexattr+0x65/0x80 fs/xattr.c:1086
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcaff18f749
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:00007ffc3d26c138 EFLAGS: 00000246 ORIG_RAX: 00000000000000c6
RAX: ffffffffffffffda RBX: 00007fcaff3e5fa0 RCX: 00007fcaff18f749
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 0000200000000240
RBP: 00007fcaff213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcaff3e5fa0 R14: 00007fcaff3e5fa0 R15: 0000000000000002