INFO: task kworker/0:7:8724 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:7 state:D
stack:21368 pid:8724 tgid:8724 ppid:2 task_flags:0x4288060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x1325/0x47d0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
rwsem_down_write_slowpath+0x4c2/0x12b0 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:1632
usb_deregister_dev+0x7c/0x210 drivers/usb/core/file.c:186
sisusb_disconnect+0x5e/0x200 drivers/usb/misc/sisusbvga/sisusbvga.c:2921
usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:461
device_remove drivers/base/dd.c:618 [inline]
device_remove+0x12a/0x180 drivers/base/dd.c:610
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664
device_del+0x376/0x9b0 drivers/base/core.c:3961
usb_disable_device+0x367/0x810 drivers/usb/core/message.c:1478
usb_disconnect+0x2e2/0x9a0 drivers/usb/core/hub.c:2350
hub_port_connect drivers/usb/core/hub.c:5412 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5712 [inline]
port_event drivers/usb/core/hub.c:5876 [inline]
hub_event+0x1d0c/0x4af0 drivers/usb/core/hub.c:5958
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
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
INFO: task syz.3.2745:13580 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.2745 state:D stack:29072 pid:13580 tgid:13579 ppid:2973 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x1325/0x47d0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
rwsem_down_read_slowpath+0x5af/0xb40 kernel/locking/rwsem.c:1114
__down_read_common kernel/locking/rwsem.c:1291 [inline]
__down_read kernel/locking/rwsem.c:1304 [inline]
down_read+0xed/0x4c0 kernel/locking/rwsem.c:1576
usb_open+0x23/0x220 drivers/usb/core/file.c:38
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x68b/0x14b0 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1052
do_open fs/namei.c:4700 [inline]
path_openat+0x2873/0x4280 fs/namei.c:4863
do_file_open+0x20e/0x430 fs/namei.c:4892
do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1385
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: 0033:0x7f221c47e84e
RSP: 002b:00007f221af16b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f221af176c0 RCX: 00007f221c47e84e
RDX: 0000000000000002 RSI: 00007f221af16c00 RDI: ffffffffffffff9c
RBP: 00007f221c55500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f221c746038 R14: 00007f221c745fa0 R15: 00007ffe5b7f7458
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff896e2b40 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff896e2b40 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff896e2b40 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
6 locks held by kworker/0:2/120:
#0: ffff8881062a7d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc900005bfd18
(
(work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffff88810af051d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#2: ffff88810af051d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5904
#3: ffff88810f37f1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#3: ffff88810f37f1d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#4: ffff8881334f01a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#4: ffff8881334f01a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#5: ffffffff8a338e68 (minor_rwsem#2){++++}-{4:4}, at: usb_register_dev+0x11d/0x570 drivers/usb/core/file.c:134
1 lock held by klogd/2847:
#0: ffff8881f57397a0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x20/0x30 kernel/sched/core.c:667
2 locks held by getty/2920:
#0: ffff888108ea00a0 (&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+0x419/0x14e0 drivers/tty/n_tty.c:2211
6 locks held by kworker/1:3/5228:
#0: ffff8881062a7d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000210fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffff88810af7d1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#2: ffff88810af7d1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5904
#3: ffff888119a811d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#3: ffff888119a811d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#4: ffff88813b4051a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#4: ffff88813b4051a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#5: ffffffff8a338e68 (minor_rwsem#2){++++}-{4:4}, at: usb_register_dev+0x11d/0x570 drivers/usb/core/file.c:134
6 locks held by kworker/0:3/5230:
#0:
ffff8881062a7d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000218fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffff88810afad1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#2: ffff88810afad1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5904
#3: ffff88813a0f31d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#3: ffff88813a0f31d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#4: ffff8881188381a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#4: ffff8881188381a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#5:
ffffffff8a338e68 (minor_rwsem#2){++++}-{4:4}, at: usb_register_dev+0x11d/0x570 drivers/usb/core/file.c:134
6 locks held by kworker/0:7/8724:
#0: ffff8881062a7d40 (
(wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000436fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffff888109fe51d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#2: ffff888109fe51d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5904
#3: ffff8881398921d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#3: ffff8881398921d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2341
#4: ffff88811dc4a1a0 (&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:1102 [inline]
, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1369
#5:
ffffffff8a338e68
(minor_rwsem#2
){++++}-{4:4}, at: usb_deregister_dev+0x7c/0x210 drivers/usb/core/file.c:186
7 locks held by kworker/1:6/10481:
#0: ffff8881062a7d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000493fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffff88810ab651d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#2: ffff88810ab651d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5904
#3: ffff88811e66a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#3: ffff88811e66a1d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#4:
ffff88811ea301a0
(
&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#5: ffff8881199c9a58 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#5: ffff8881199c9a58 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#6: ffffffff8a338e68 (minor_rwsem#2){++++}-{4:4}, at: usb_register_dev+0x11d/0x570 drivers/usb/core/file.c:134
2 locks held by syz.1.2742/13581:
#0: ffffffff8a338e68 (minor_rwsem#2){++++}-{4:4}, at: usb_open+0x23/0x220 drivers/usb/core/file.c:38
#1: ffff8881057c38c8 (&(sisusb->lock)){+.+.}-{4:4}, at: sisusb_open+0xb6/0x4b0 drivers/usb/misc/sisusbvga/sisusbvga.c:2213
1 lock held by syz.3.2745/13580:
#0:
ffffffff8a338e68
(
minor_rwsem
#2){++++}-{4:4}, at: usb_open+0x23/0x220 drivers/usb/core/file.c:38
1 lock held by syz.5.2796/14600:
#0: ffffffff8a338e68 (minor_rwsem#2){++++}-{4:4}, at: usb_open+0x23/0x220 drivers/usb/core/file.c:38
1 lock held by syz.6.2934/15342:
#0: ffffffff8a338e68 (minor_rwsem#2){++++}-{4:4}, at: usb_open+0x23/0x220 drivers/usb/core/file.c:38
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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:122
nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65
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: 8218 Comm: kworker/0:6 Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events legacy_dvb_usb_read_remote_control
RIP: 0010:io_serial_in+0x87/0xb0 drivers/tty/serial/8250/8250_port.c:402
Code: 82 88 fe 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1a 66 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c e9 cd 85 53 04 e8 38 e8 f0 fe eb a2 e8 c1 e8
RSP: 0018:ffffc900138675f8 EFLAGS: 00000002
RAX: dffffc0000000060 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffffff832b8160 RDI: ffffffff94249da0
RBP: ffffffff94249d60 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000060 R14: fffffbfff2849406 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888268636000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555595273908 CR3: 0000000122bf8000 CR4: 00000000003506f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x13a/0x210 drivers/tty/serial/8250/8250_port.c:1982
wait_for_xmitr+0x28/0x360 drivers/tty/serial/8250/8250_port.c:2001
serial8250_console_write+0x414/0x1a50 drivers/tty/serial/8250/8250_port.c:3393
console_emit_next_record kernel/printk/printk.c:3183 [inline]
console_flush_one_record+0x790/0xe50 kernel/printk/printk.c:3269
console_flush_all kernel/printk/printk.c:3343 [inline]
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0x103/0x260 kernel/printk/printk.c:3413
vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
_printk+0xcf/0x110 kernel/printk/printk.c:2504
m920x_read drivers/media/usb/dvb-usb/m920x.c:40 [inline]
m920x_rc_query.cold+0x2b/0x30 drivers/media/usb/dvb-usb/m920x.c:188
legacy_dvb_usb_read_remote_control+0x10c/0x4f0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:123
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
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