INFO: task kworker/1:1:28 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:1 state:D stack:21592 pid:28 tgid:28 ppid:2 task_flags:0x4208060 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 kernfs_add_one+0x38/0xaa0 fs/kernfs/dir.c:825 kernfs_create_dir_ns+0x157/0x2b0 fs/kernfs/dir.c:1130 sysfs_create_dir_ns+0x13a/0x2b0 fs/sysfs/dir.c:59 create_dir lib/kobject.c:73 [inline] kobject_add_internal+0x2c8/0x930 lib/kobject.c:240 kobject_add_varg lib/kobject.c:374 [inline] kobject_add+0x16a/0x1e0 lib/kobject.c:426 device_add+0x294/0x1970 drivers/base/core.c:3695 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268 usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:293 call_driver_probe drivers/base/dd.c:628 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:706 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153 bus_probe_device+0x64/0x160 drivers/base/bus.c:620 device_add+0x121d/0x1970 drivers/base/core.c:3772 usb_new_device.part.0+0xcc2/0x1686 drivers/usb/core/hub.c:2708 usb_new_device drivers/usb/core/hub.c:5833 [inline] hub_port_connect drivers/usb/core/hub.c:5580 [inline] hub_port_connect_change drivers/usb/core/hub.c:5720 [inline] port_event drivers/usb/core/hub.c:5884 [inline] hub_event.cold+0x51a/0xe9d drivers/usb/core/hub.c:5966 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 Showing all locks held in the system: 1 lock held by rcu_exp_gp_kthr/17: #0: ffff8881f56397a0 (&rq->__lock ){-.-.}-{2:2} , at: raw_spin_rq_lock_nested kernel/sched/core.c:667 [inline] , at: raw_spin_rq_lock kernel/sched/sched.h:1653 [inline] , at: rq_lock kernel/sched/sched.h:1991 [inline] , at: __schedule+0x2dc/0x47d0 kernel/sched/core.c:7108 3 locks held by kworker/1:0/23: #0: ffff88810006b140 ( (wq_completion)events ){+.+.}-{0:0} , at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297 #1: ffffc9000018fd18 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298 #2: ffffffff896ee668 ( rcu_state.exp_mutex ){+.+.}-{4:4} , at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 3 locks held by kworker/1:1/28: 1 lock held by khungtaskd/30: #0: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:2/36: #0: ffff888100e98940 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297 #1: ffffc90000267d18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298 #2: ffffffff8ab0c968 ( pernet_ops_rwsem ){++++}-{4:4} , at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:673 2 locks held by kworker/0:2/120: 2 locks held by getty/2920: #0: ffff8881157120a0 (&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 1 lock held by syz-executor/2962: #0: ffff8881f57397a0 ( &rq->__lock ){-.-.}-{2:2} , at: raw_spin_rq_lock_nested kernel/sched/core.c:667 [inline] , at: raw_spin_rq_lock kernel/sched/sched.h:1653 [inline] , at: rq_lock kernel/sched/sched.h:1991 [inline] , at: __schedule+0x2dc/0x47d0 kernel/sched/core.c:7108 1 lock held by syz-executor/2972: #0: ffffffff896ee668 ( rcu_state.exp_mutex ){+.+.}-{4:4} , at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 3 locks held by kworker/1:3/5223: 2 locks held by kworker/0:4/5234: 6 locks held by kworker/0:6/5272: 9 locks held by kworker/0:7/5344: 2 locks held by syz-executor/6096: 2 locks held by syz-executor/6099: 1 lock held by syz-executor/6100: 1 lock held by modprobe/6103: 2 locks held by modprobe/6106: 5 locks held by syz-executor/6108: 2 locks held by modprobe/6109: 1 lock held by modprobe/6110: ============================================= 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: yealink 5-1:36.0: urb_ctl_callback - urb status -71 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5347 Comm: kworker/0:8 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_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:408 Code: 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 1c 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d c3 cc cc cc cc e8 d1 c9 f0 fe eb a0 e8 5a ca f0 RSP: 0018:ffffc90004477698 EFLAGS: 00000002 RAX: 0000000000000039 RBX: 00000000000003f8 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: ffffffff832bb805 RDI: ffffffff9424d0e0 RBP: ffffffff9424d0a0 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000039 R14: ffffffff9408d8a8 R15: ffffffff832bb7a0 FS: 0000000000000000(0000) GS:ffff888268633000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd95f7b26d0 CR3: 0000000134802000 CR4: 00000000003506f0 Call Trace: serial_port_out include/linux/serial_core.h:813 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3245 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3307 [inline] serial8250_console_write+0xe2c/0x1a50 drivers/tty/serial/8250/8250_port.c:3385 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 yealink 5-1:36.0: urb_irq_callback - urb status -71 yealink 5-1:36.0: unexpected response 0 yealink 5-1:36.0: urb_ctl_callback - urb status -71 yealink 5-1:36.0: urb_irq_callback - urb status -71 yealink 5-1:36.0: unexpected response 0 yealink 5-1:36.0: urb_ctl_callback - urb status -71 yealink 5-1:36.0: urb_irq_callback - urb status -71 yealink 5-1:36.0: unexpected response 0 yealink 5-1:36.0: urb_ctl_callback - urb status -71 yealink 5-1:36.0: urb_irq_callback - urb status -71 yealink 5-1:36.0: unexpected response 0 yealink 5-1:36.0: urb_ctl_callback - urb status -71 yealink 5-1:36.0: urb_irq_callback - urb status -71 yealink 5-1:36.0: unexpected response 0 yealink 5-1:36.0: urb_ctl_callback - urb status -71 yealink 5-1:36.0: urb_irq_callback - urb status -71 yealink 5-1:36.0: unexpected response 0 yealink 5-1:36.0: urb_ctl_callback - urb status -71 yealink 5-1:36.0: urb_irq_callback - urb status -71