INFO: task syz.6.1242:10788 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.1242 state:D stack:26504 pid:10788 tgid:10781 ppid:7356 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7307
rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
device_lock include/linux/device.h:914 [inline]
usbdev_open+0x16e/0x790 drivers/usb/core/devio.c:1054
chrdev_open+0x4cf/0x5e0 fs/char_dev.c:414
do_dentry_open+0x9b1/0x1350 fs/open.c:965
vfs_open+0x3b/0x350 fs/open.c:1097
do_open fs/namei.c:3975 [inline]
path_openat+0x2ef1/0x3840 fs/namei.c:4134
do_filp_open+0x1fa/0x410 fs/namei.c:4161
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3783ddd810
RSP: 002b:00007f3781ffbb70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f3783ddd810
RDX: 0000000000000002 RSI: 00007f3781ffbc10 RDI: 00000000ffffff9c
RBP: 00007f3781ffbc10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd
R13: 00007f3784036218 R14: 00007f3784036180 R15: 00007fff3cbbf378
Showing all locks held in the system:
1 lock held by khungtaskd/39:
#0: ffffffff8d5aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d5aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d5aa4c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by pvrusb2-context/2371:
#0: ffff888034e3c1b8 (&hdw->big_lock_mutex){+.+.}-{4:4}, at: pvr2_hdw_initialize+0xc6/0x3ac0 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2326
#1: ffffffff8d4513e0 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xf0/0x2b0 kernel/umh.c:214
2 locks held by getty/5563:
#0: ffff88823bf748a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222
2 locks held by kworker/u9:3/5806:
#0: ffff888024cb1138 ((wq_completion)nbd1-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff888024cb1138 ((wq_completion)nbd1-recv){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc90004cd7ba0 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc90004cd7ba0 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
6 locks held by kworker/1:5/5881:
#0: ffff88801ee90138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88801ee90138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc900051a7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc900051a7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffff88814633c188 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#2: ffff88814633c188 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
#3: ffff88803901a188 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#3: ffff88803901a188 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0xde/0x940 drivers/usb/core/hub.c:2335
#4: ffff88805e5b3150 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#4: ffff88805e5b3150 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1096 [inline]
#4: ffff88805e5b3150 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x800 drivers/base/dd.c:1294
#5: ffff888034e3c1b8 (&hdw->big_lock_mutex){+.+.}-{4:4}, at: pvr2_hdw_disconnect+0x6d/0x500 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2710
4 locks held by udevd/9033:
#0: ffff88805eb07608 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb8/0xe20 fs/seq_file.c:182
#1: ffff888030eb4078 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
#2: ffff888031bb6698 (kn->active#27){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888031bb6698 (kn->active#27){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173
#3: ffff88803901a188 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline]
#3: ffff88803901a188 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
1 lock held by syz.6.1242/10788:
#0: ffff88814633c188 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#0: ffff88814633c188 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x790 drivers/usb/core/devio.c:1054
5 locks held by kworker/u8:40/11030:
1 lock held by syz.3.1426/11307:
#0: ffff88814633c188 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#0: ffff88814633c188 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x790 drivers/usb/core/devio.c:1054
2 locks held by syz-executor/13498:
1 lock held by syz.7.2413/13700:
#0: ffffffff8d5afe70 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3820
4 locks held by syz.0.2414/13702:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400
Code: e8 de 09 ba fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 5f c1 1b fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 0a 4b bf 05 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000167870 EFLAGS: 00000202
RAX: 1ffffffff31d1700 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff98e8c0f0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8504b3d0 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff98e8be60 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888126efc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000000c0 CR3: 000000006d368000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:137 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline]
wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1961
fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3234 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3257 [inline]
serial8250_console_write+0x11bd/0x1b40 drivers/tty/serial/8250/8250_port.c:3342
console_emit_next_record kernel/printk/printk.c:3091 [inline]
console_flush_all+0x666/0xb40 kernel/printk/printk.c:3199
__console_flush_and_unlock+0x9b/0x160 kernel/printk/printk.c:3258
legacy_kthread_func+0x13b/0x1a0 kernel/printk/printk.c:3611
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245