INFO: task kworker/1:1:37 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:37 tgid:37 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x12fc/0x3b80 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083 rwsem_down_write_slowpath+0x521/0x1310 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write+0x1d6/0x200 kernel/locking/rwsem.c:1591 kernfs_add_one+0x38/0x840 fs/kernfs/dir.c:791 kernfs_create_dir_ns+0xfc/0x1a0 fs/kernfs/dir.c:1093 sysfs_create_dir_ns+0x13a/0x2b0 fs/sysfs/dir.c:59 create_dir lib/kobject.c:73 [inline] kobject_add_internal+0x2c4/0x9b0 lib/kobject.c:240 kobject_add_varg lib/kobject.c:374 [inline] kobject_add+0x16e/0x240 lib/kobject.c:426 device_add+0x288/0x1aa0 drivers/base/core.c:3627 usb_new_device+0xd07/0x1a60 drivers/usb/core/hub.c:2695 hub_port_connect drivers/usb/core/hub.c:5567 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x2fce/0x5060 drivers/usb/core/hub.c:5953 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x56d/0x700 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 khungtaskd/30: #0: ffffffff892c89e0 ( rcu_read_lock ){....}-{1:3} , at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] , at: rcu_read_lock include/linux/rcupdate.h:867 [inline] , at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:1/32: 7 locks held by kworker/0:2/1118: 2 locks held by kworker/u8:7/2647: 2 locks held by getty/2915: #0: ffff8881153f20a0 (&tty->ldisc_sem ){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000432f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/2962: #0: ffffffff892d3f78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by syz-executor/2965: #0: ffffffff892d3f78 (rcu_state.exp_mutex){+.+.}-{4:4} , at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311 4 locks held by udevd/5186: #0: ffff888134bd4418 ( &p->lock){+.+.}-{4:4} , at: seq_read_iter+0xe1/0x12d0 fs/seq_file.c:182 #1: ffff88813b2a9888 ( &of->mutex #2 ){+.+.}-{4:4} , at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888123213698 ( kn->active#18){++++}-{0:0} , at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] , at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88813b154198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline] (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 7 locks held by kworker/0:4/5215: 7 locks held by kworker/0:5/5224: 4 locks held by udevd/5239: #0: ffff888134c7b668 (&p->lock ){+.+.}-{4:4} , at: seq_read_iter+0xe1/0x12d0 fs/seq_file.c:182 #1: ffff888133e41888 (&of->mutex#2){+.+.}-{4:4} , at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888123de02d8 (kn->active #18){++++}-{0:0} , at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] , at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88811d034198 (&dev->mutex ){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline] ){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 3 locks held by kworker/1:5/5356: 1 lock held by syz-executor/5640: #0: ffff888100ac5988 (&root->kernfs_rwsem ){++++}-{4:4}, at: kernfs_dop_revalidate+0xa5/0x740 fs/kernfs/dir.c:1180 1 lock held by syz-executor/5641: #0: ffff888100ac5988 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x740 fs/kernfs/dir.c:1180 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/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+0xf3f/0x1170 kernel/hung_task.c:495 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x56d/0x700 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 4-1:36.0: urb_ctl_callback - urb status -71 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 1118 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events legacy_dvb_usb_read_remote_control RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:407 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 e9 86 9c 69 04 e8 f1 c4 00 ff eb a0 e8 7a c5 00 RSP: 0000:ffffc900000074f0 EFLAGS: 00000006 RAX: 0000000000000000 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: ffffffff82ddc225 RDI: ffffffff93bdc700 RBP: ffffffff93bdc6c0 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff93bdc6c0 R15: ffffffff93bdc980 FS: 0000000000000000(0000) GS:ffff888268ea0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f55ae3d22e0 CR3: 0000000116f62000 CR4: 00000000003506f0 Call Trace: serial_out drivers/tty/serial/8250/8250.h:142 [inline] serial8250_clear_IER+0x9e/0xc0 drivers/tty/serial/8250/8250_port.c:714 serial8250_console_write+0x255/0x1890 drivers/tty/serial/8250/8250_port.c:3307 console_emit_next_record kernel/printk/printk.c:3111 [inline] console_flush_all+0x801/0xc60 kernel/printk/printk.c:3199 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xd8/0x210 kernel/printk/printk.c:3298 vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423 dev_vprintk_emit drivers/base/core.c:4914 [inline] dev_printk_emit+0xfa/0x140 drivers/base/core.c:4925 __dev_printk+0xf5/0x270 drivers/base/core.c:4937 _dev_err+0xe4/0x120 drivers/base/core.c:4980 urb_ctl_callback+0x1eb/0x2f0 drivers/input/misc/yealink.c:456 __usb_hcd_giveback_urb+0x38b/0x610 drivers/usb/core/hcd.c:1661 usb_hcd_giveback_urb+0x39b/0x450 drivers/usb/core/hcd.c:1745 dummy_timer+0x1809/0x3a00 drivers/usb/gadget/udc/dummy_hcd.c:1995 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1841 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1858 handle_softirqs+0x208/0x8d0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xfa/0x160 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:console_flush_all+0x9a2/0xc60 kernel/printk/printk.c:3200 Code: 00 e8 42 c3 28 00 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 d0 c8 20 00 48 85 db 0f 85 55 01 00 00 e8 52 cd 20 00 fb 4c 89 e0 <48> c1 e8 03 42 80 3c 38 00 0f 84 11 ff ff ff 4c 89 e7 e8 b7 06 81 RSP: 0000:ffffc90001d9f818 EFLAGS: 00000293 RAX: ffffffff897fd7f8 RBX: 0000000000000000 RCX: ffffffff815d8100 RDX: ffff88810ff2ba00 RSI: ffffffff815d810e RDI: 0000000000000007 RBP: 0000000000000001 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffffffff897fd7f8 R13: ffffffff897fd7a0 R14: ffffc90001d9f8a8 R15: dffffc0000000000 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xd8/0x210 kernel/printk/printk.c:3298 vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423 _printk+0xc7/0x100 kernel/printk/printk.c:2448 m920x_read drivers/media/usb/dvb-usb/m920x.c:40 [inline] m920x_rc_query+0x496/0x770 drivers/media/usb/dvb-usb/m920x.c:193 legacy_dvb_usb_read_remote_control+0x10c/0x4f0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:123 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x56d/0x700 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245