INFO: task kworker/1:6:5284 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:6 state:D stack:21128 pid:5284 tgid:5284 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_add_one+0x38/0x850 fs/kernfs/dir.c:826 kernfs_create_link+0x1a9/0x240 fs/kernfs/symlink.c:48 sysfs_do_create_link_sd+0x90/0x140 fs/sysfs/symlink.c:44 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline] sysfs_create_link+0x61/0xc0 fs/sysfs/symlink.c:92 driver_sysfs_add+0x91/0x2d0 drivers/base/dd.c:490 really_probe+0x146/0xa60 drivers/base/dd.c:697 __driver_probe_device+0x22e/0x480 drivers/base/dd.c:871 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:901 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1029 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1101 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1156 bus_probe_device+0x64/0x160 drivers/base/bus.c:613 device_add+0x1210/0x1950 drivers/base/core.c:3706 usb_new_device.cold+0x685/0x115c 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+0x314d/0x4af0 drivers/usb/core/hub.c:5953 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 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/0:1/11: 1 lock held by khungtaskd/30: #0: ffffffff896de960 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff896de960 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff896de960 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 6 locks held by klogd/2852: 1 lock held by udevd/2863: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 2 locks held by getty/2926: #0: ffff8881165520a0 ( &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 2 locks held by kworker/0:2/5209: 7 locks held by kworker/0:4/5222: 2 locks held by kworker/1:3/5239: #0: ffff88810006b140 ( (wq_completion)events ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc90001e3fd18 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 6 locks held by kworker/1:6/5284: #0: ffff8881062f4540 ((wq_completion)usb_hub_wq ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc9000212fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 #2: ffff88810cb151d8 ( &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: ffff888133d981d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] ffff888133d981d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff888100e87aa0 (&root->kernfs_supers_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x49/0x120 fs/kernfs/dir.c:1792 #5: ffff888100e87980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x51/0x120 fs/kernfs/dir.c:1793 1 lock held by syz-executor/10967: 2 locks held by kworker/u8:7/10982: #0: ffff8881000ac940 ( (wq_completion)events_unbound #2 ){+.+.}-{0:0}, at: raw_spin_rq_lock_nested kernel/sched/core.c:652 [inline] ){+.+.}-{0:0}, at: raw_spin_rq_lock kernel/sched/sched.h:1624 [inline] ){+.+.}-{0:0}, at: rq_lock kernel/sched/sched.h:1968 [inline] ){+.+.}-{0:0}, at: __schedule+0x2bc/0x47e0 kernel/sched/core.c:7064 #1: ffffc90003eefd18 ( (work_completion)(&sub_info->work) ){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 4 locks held by udevd/13192: #0: ffff8881349dcbd8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88810934d080 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff88812d9362d8 (kn->active#9){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] ffff88812d9362d8 (kn->active#9){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88811416c1d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff88811416c1d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 1 lock held by udevd/13201: #0: ffff888100e87980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 1 lock held by udevd/13247: #0: ffff888100e87980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 4 locks held by udevd/13260: #0: ffff8881252e4bd8 ( &p->lock ){+.+.}-{4:4} , at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88811e50d480 ( &of->mutex #2 ){+.+.}-{4:4} , at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888104ae61e8 ( kn->active #9 ){++++}-{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: ffff88811b1421d8 ( &dev->mutex ){....}-{4:4} , at: device_lock_interruptible include/linux/device.h:1045 [inline] , at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 6 locks held by kworker/0:3/15794: 5 locks held by kworker/0:5/18389: 2 locks held by kworker/0:6/18950: 4 locks held by kworker/0:7/19091: #0: ffff88810006b140 ((wq_completion)events ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc9000365fd18 ( kernfs_notify_work ){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 #2: ffff888100e87aa0 ( &root->kernfs_supers_rwsem ){++++}-{4:4} , at: kernfs_notify_workfn+0xf7/0x5f0 fs/kernfs/file.c:932 #3: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_notify_workfn+0xff/0x5f0 fs/kernfs/file.c:933 5 locks held by kworker/u8:0/19104: #0: ffff888100e98940 ( (wq_completion)netns ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc900036bfd18 (net_cleanup_work ){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 #2: ffffffff8aadc468 ( pernet_ops_rwsem ){++++}-{4:4} , at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:673 #3: ffffffff8aaf4fe0 ( rtnl_mutex ){+.+.}-{4:4} , at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline] , at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:248 #4: ffffffff896ea4a8 ( rcu_state.exp_mutex ){+.+.}-{4:4} , at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 2 locks held by syz.8.3764/21074: #0: ffff888100e87aa0 ( &root->kernfs_supers_rwsem ){++++}-{4:4} , at: kernfs_remove_by_name_ns+0x49/0x120 fs/kernfs/dir.c:1792 #1: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_remove_by_name_ns+0x51/0x120 fs/kernfs/dir.c:1793 1 lock held by syz.9.3766/21084: #0: ffffffff896ea4a8 ( rcu_state.exp_mutex ){+.+.}-{4:4} , at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by syz-executor/21087: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 1 lock held by syz-executor/21091: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 1 lock held by syz-executor/21092: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 1 lock held by syz-executor/21095: #0: ffffffff8aaf4fe0 ( rtnl_mutex ){+.+.}-{4:4} , at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] , at: inet_rtm_newaddr+0x30c/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/21098: #0: ffffffff8aaf4fe0 ( rtnl_mutex ){+.+.}-{4:4} , at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] , at: inet_rtm_newaddr+0x30c/0x18b0 net/ipv4/devinet.c:978 ============================================= 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 05/09/2026 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: yealink 6-1:36.0: unexpected response 0 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 2852 Comm: klogd Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:246 Code: ae d1 44 0b 48 8b 80 00 16 00 00 c3 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <65> 8b 05 99 d1 44 0b 49 89 f8 49 89 f1 49 89 d2 65 48 8b 3d 70 d1 RSP: 0018:ffffc90000007088 EFLAGS: 00000002 RAX: 0000000000000008 RBX: 0000000000000001 RCX: ffffffff876b6ade RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000001 RBP: ffffffff888be4a0 R08: 0000000000000001 R09: 0000000000000000 R10: 000000000000000a R11: 0000000000975d50 R12: 0000000000000001 R13: 0000000000000008 R14: 0000000000000001 R15: ffffc900000072c9 FS: 00007fc17d66bc80(0000) GS:ffff8882686a5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c38ac5d CR3: 0000000117a52000 CR4: 00000000003506f0 Call Trace: __sanitizer_cov_trace_switch+0x54/0x90 kernel/kcov.c:351 vsnprintf+0x1fe/0x1240 lib/vsprintf.c:2892 snprintf+0xc7/0x100 lib/vsprintf.c:3042 print_caller kernel/printk/printk.c:1368 [inline] info_print_prefix+0x134/0x350 kernel/printk/printk.c:1387 record_print_text+0x143/0x3c0 kernel/printk/printk.c:1434 printk_get_next_message+0x2d1/0x6c0 kernel/printk/printk.c:3072 console_emit_next_record kernel/printk/printk.c:3137 [inline] console_flush_one_record+0x67c/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 dev_vprintk_emit+0x394/0x3e0 drivers/base/core.c:4930 dev_printk_emit+0xd2/0x10d drivers/base/core.c:4941 __dev_printk+0xcb/0x100 drivers/base/core.c:4953 _dev_err+0xef/0x127 drivers/base/core.c:4996 urb_irq_callback.cold+0x81/0xfd drivers/input/misc/yealink.c:435 __usb_hcd_giveback_urb+0x38d/0x610 drivers/usb/core/hcd.c:1657 usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741 dummy_timer+0xda1/0x36c0 drivers/usb/gadget/udc/dummy_hcd.c:2005 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x470/0xa00 kernel/time/hrtimer.c:1994 hrtimer_run_softirq+0x17d/0x2c0 kernel/time/hrtimer.c:2011 handle_softirqs+0x1dd/0x9e0 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xac/0xe0 kernel/softirq.c:510 __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x5db/0x710 net/core/skbuff.c:697 alloc_skb include/linux/skbuff.h:1385 [inline] alloc_skb_with_frags+0xdd/0x760 net/core/skbuff.c:6766 sock_alloc_send_pskb+0x801/0x980 net/core/sock.c:2998 unix_dgram_sendmsg+0x3c7/0x1810 net/unix/af_unix.c:2141 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] __sys_sendto+0x468/0x4b0 net/socket.c:2265 __do_sys_sendto net/socket.c:2272 [inline] __se_sys_sendto net/socket.c:2268 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2268 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: 0033:0x7fc17d7bb407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffee69ea1c0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007fc17d66bc80 RCX: 00007fc17d7bb407 RDX: 0000000000000053 RSI: 00007ffee69ea300 RDI: 0000000000000003 RBP: 00007ffee69ea730 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffee69ea748 R13: 00007ffee69ea300 R14: 0000000000000038 R15: 00007ffee69ea300