INFO: task kworker/0:0:9 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:0 state:D
stack:21480 pid:9 tgid:9 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1138/0x47e0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
rwsem_down_write_slowpath+0x4c2/0x12c0 kernel/locking/rwsem.c:1215
__down_write_common kernel/locking/rwsem.c:1347 [inline]
__down_write kernel/locking/rwsem.c:1356 [inline]
down_write+0x1c7/0x1f0 kernel/locking/rwsem.c:1626
kernfs_remove_by_name_ns+0x51/0x120 fs/kernfs/dir.c:1793
usb_disconnect+0x488/0x9a0 drivers/usb/core/hub.c:2353
hub_port_connect drivers/usb/core/hub.c:5407 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
port_event drivers/usb/core/hub.c:5871 [inline]
hub_event+0x1d0c/0x4af0 drivers/usb/core/hub.c:5953
process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302
process_scheduled_works kernel/workqueue.c:3385 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
5 locks held by kworker/0:0/9:
#0:
ffff888105af8940
(
(wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277
#1:
ffffc9000009fd18
(
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278
#2:
ffff88810bfd31d8
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
#3:
ffff88810bfd0560
(
&port_dev->status_lock
){+.+.}-{4:4}
, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline]
, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline]
, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
, at: port_event drivers/usb/core/hub.c:5871 [inline]
, at: hub_event+0x2bd2/0x4af0 drivers/usb/core/hub.c:5953
#4:
ffff88810cac5160
(
hcd->address0_mutex
){+.+.}-{4:4}
, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline]
, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
, at: port_event drivers/usb/core/hub.c:5871 [inline]
, at: hub_event+0x2bfb/0x4af0 drivers/usb/core/hub.c:5953
5 locks held by ksoftirqd/1/22:
4 locks held by kworker/1:0/23:
1 lock held by khungtaskd/30:
#0:
ffffffff896de8e0
(
rcu_read_lock
){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
1 lock held by udevd/2856:
#0:
ffff888100e87980
(
&root->kernfs_rwsem
){++++}-{4:4}
, at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218
2 locks held by getty/2918:
#0:
ffff8881166390a0
(
&tty->ldisc_sem
){++++}-{0:0}
, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1:
ffffc900000452e8
(
&ldata->atomic_read_lock
){+.+.}-{4:4}
, at: n_tty_read+0x419/0x14f0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/2971:
#0:
ffffffff896ea428
(rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by syz-executor/2978:
#0: ffffffff896ea428 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
1 lock held by modprobe/5695:
2 locks held by modprobe/5698:
3 locks held by modprobe/5700:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5657 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:146 [inline]
RIP: 0010:lock_acquire kernel/locking/lockdep.c:5869 [inline]
RIP: 0010:lock_acquire+0x17d/0x370 kernel/locking/lockdep.c:5825
Code: 00 00 85 d2 0f 85 98 00 00 00 9c 8f 04 24 fa 48 c7 c7 03 1e 16 89 e8 a2 a7 de 05 45 89 e8 44 89 e1 89 da 65 ff 05 ab be 68 0b <4c> 8b 14 24 44 89 f6 48 89 ef 41 81 e2 00 02 00 00 4c 89 14 24 4d
RSP: 0018:ffffc90003fef7a8 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff89161e03 RDI: ffffffff87b08de0
RBP: ffffffff896de8e0 R08: 0000000000000000 R09: 0000000000000000
R10: ffff888100e8791f R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000555566be2500(0000) GS:ffff8882686a5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f372734a368 CR3: 000000010df0a000 CR4: 00000000003506f0
Call Trace:
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:838 [inline]
class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
kernfs_root+0x34/0x2a0 fs/kernfs/kernfs-internal.h:74
kernfs_add_one+0x4ef/0x850 fs/kernfs/dir.c:868
__kernfs_create_file+0x295/0x350 fs/kernfs/file.c:1086
sysfs_add_file_mode_ns+0x207/0x3c0 fs/sysfs/file.c:313
sysfs_merge_group+0x194/0x340 fs/sysfs/group.c:382
dpm_sysfs_add+0x237/0x280 drivers/base/power/sysfs.c:704
device_add+0x9ef/0x1950 drivers/base/core.c:3651
netdev_register_kobject+0x1a9/0x3d0 net/core/net-sysfs.c:2343
register_netdevice+0x13ca/0x2280 net/core/dev.c:11420
register_netdev+0x34/0x50 net/core/dev.c:11536
loopback_net_init+0x7a/0x170 drivers/net/loopback.c:218
ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137
setup_net+0x118/0x3a0 net/core/net_namespace.c:446
copy_net_ns+0x46f/0x7c0 net/core/net_namespace.c:579
create_new_namespaces+0x3ea/0xac0 kernel/nsproxy.c:132
unshare_nsproxy_namespaces+0xf2/0x220 kernel/nsproxy.c:234
ksys_unshare+0x438/0xab0 kernel/fork.c:3243
__do_sys_unshare kernel/fork.c:3317 [inline]
__se_sys_unshare kernel/fork.c:3315 [inline]
__x64_sys_unshare+0x31/0x40 kernel/fork.c:3315
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0x7f0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f931097e127
Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 10 01 00 00 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:00007ffea8acf7b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f9310bf5f40 RCX: 00007f931097e127
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007f9310bf67b8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffea8acf9f8 R15: 0000000000000000