INFO: task kworker/0:0:9 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:0 state:D stack:20920 pid:9 tgid:9 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_dir_ns+0xfc/0x1a0 fs/kernfs/dir.c:1131 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+0x294/0x1950 drivers/base/core.c:3629 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:291 call_driver_probe drivers/base/dd.c:631 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:709 __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 INFO: task udevd:2854 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:24600 pid:2854 tgid:2854 ppid:1 task_flags:0x400140 flags:0x00080000 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_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/0x450 kernel/locking/rwsem.c:1570 kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 d_revalidate fs/namei.c:1030 [inline] d_revalidate fs/namei.c:1026 [inline] lookup_fast+0x3c7/0x600 fs/namei.c:1876 walk_component fs/namei.c:2274 [inline] link_path_walk+0x7d4/0x1cc0 fs/namei.c:2652 path_openat+0x1be/0x31a0 fs/namei.c:4854 do_file_open+0x20e/0x430 fs/namei.c:4887 do_sys_openat2+0x10d/0x1e0 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1381 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: 0033:0x7fa708ee1407 RSP: 002b:00007ffc38b645d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fa708df3880 RCX: 00007fa708ee1407 RDX: 0000000000080000 RSI: 00007ffc38b64750 RDI: ffffffffffffff9c RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055f01dfdb7f5 R13: 000055f01dfdb7f5 R14: 0000000000000001 R15: 0000000000000000 INFO: task udevd:5214 blocked for more than 145 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:23704 pid:5214 tgid:5214 ppid:2854 task_flags:0x400140 flags:0x00080000 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_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/0x450 kernel/locking/rwsem.c:1570 kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 d_revalidate fs/namei.c:1030 [inline] d_revalidate fs/namei.c:1026 [inline] lookup_fast+0x3c7/0x600 fs/namei.c:1876 walk_component fs/namei.c:2274 [inline] link_path_walk+0x7d4/0x1cc0 fs/namei.c:2652 path_openat+0x1be/0x31a0 fs/namei.c:4854 do_file_open+0x20e/0x430 fs/namei.c:4887 do_sys_openat2+0x10d/0x1e0 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1381 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: 0033:0x7fa708ee1407 RSP: 002b:00007ffc38b5ffb0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fa708df3880 RCX: 00007fa708ee1407 RDX: 0000000000080000 RSI: 00007ffc38b60130 RDI: ffffffffffffff9c RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055f01dfdb7f5 R13: 000055f01dfdb7f5 R14: 0000000000000001 R15: 000055f01dff6140 Showing all locks held in the system: 10 locks held by kworker/0:0/9: 5 locks held by kworker/0:1/11: #0: ffff8881056ab940 ( (wq_completion)usb_hub_wq ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc900000bfd18 ( (work_completion)(&hub->events) ){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 #2: ffff88810bf0d1d8 ( &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: ffff88813cd6f1d8 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:1040 [inline] , at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_activate fs/kernfs/dir.c:1463 [inline] , at: kernfs_add_one+0x54f/0x850 fs/kernfs/dir.c:869 1 lock held by khungtaskd/30: #0: ffffffff896de960 ( rcu_read_lock ){....}-{1:3} , at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] , at: rcu_read_lock include/linux/rcupdate.h:838 [inline] , at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:1/32: #0: ffff888100e98940 ( (wq_completion)netns ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc90000227d18 ( 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: ffffffff896ea4a8 ( rcu_state.exp_mutex ){+.+.}-{4:4} , at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 3 locks held by kworker/0:2/1123: 1 lock held by udevd/2854: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 2 locks held by getty/2918: #0: ffff888115a990a0 (&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 1 lock held by syz-executor/2969: #0: ffffffff896ea4a8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 4 locks held by udevd/5167: #0: ffff88811e9982d8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88811e727080 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888134bbea58 ( kn->active #23){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #23){.+.+}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff888104eb71d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] (&dev->mutex){....}-{4:4}, at: product_show+0x26/0xa0 drivers/usb/core/sysfs.c:141 6 locks held by kworker/0:3/5292: #0: ffff8881056ab940 ( (wq_completion)usb_hub_wq ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc90002defd18 ( (work_completion)(&hub->events) ){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 #2: ffff88810bbe51d8 ( &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: ffff888104eb71d8 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:1040 [inline] , at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336 #4: ffff888112b9a1a0 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:1040 [inline] , at: __device_driver_lock drivers/base/dd.c:1174 [inline] , at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1372 #5: ffffffff8aaf4fe0 ( rtnl_mutex ){+.+.}-{4:4} , at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] , at: rtnl_net_dev_lock+0x146/0x360 net/core/dev.c:2162 5 locks held by kworker/0:5/5310: 1 lock held by udevd/5347: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 1 lock held by syz-executor/5567: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 1 lock held by syz-executor/5570: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 1 lock held by syz-executor/5572: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 1 lock held by syz-executor/5574: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 1 lock held by syz-executor/5575: #0: ffff888100e87980 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1218 ============================================= 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 4-1:36.0: urb_irq_callback - urb status -71 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: usb_hub_wq hub_event 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 e9 96 fa 4d 04 e8 61 ab f5 fe eb a0 e8 ea ab f5 RSP: 0018:ffffc90000007490 EFLAGS: 00000002 RAX: 0000000000000039 RBX: 00000000000003f8 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: ffffffff8322f515 RDI: ffffffff941da800 RBP: ffffffff941da7c0 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000039 R14: 0000000000000010 R15: ffffffff8322f4b0 FS: 0000000000000000(0000) GS:ffff8882686a5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2df63fff CR3: 0000000116b82000 CR4: 00000000003506f0 Call Trace: serial_port_out include/linux/serial_core.h:811 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3220 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3282 [inline] serial8250_console_write+0xde8/0x1900 drivers/tty/serial/8250/8250_port.c:3360 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 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+0x41/0xfd drivers/input/misc/yealink.c:418 __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:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x160/0x210 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 fb 66 68 0b 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 86 24 61 09 0f 82 a4 02 00 00 8b 35 0e 34 61 09 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 9d 66 68 0b 0f 85 ed 02 00 00 48 83 c4 RSP: 0018:ffffc900000bf570 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff890a9792 RDI: ffffffff87b08200 RBP: ffffffff896de960 R08: 0000000084e9da8d R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __reset_page_owner+0x84/0x190 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1397 [inline] __free_frozen_pages+0x6d8/0xf60 mm/page_alloc.c:2938 vfree mm/vmalloc.c:3472 [inline] vfree+0x15f/0x8d0 mm/vmalloc.c:3436 kcov_put kernel/kcov.c:442 [inline] kcov_put+0x2a/0x40 kernel/kcov.c:438 hub_event+0xdc6/0x4af0 drivers/usb/core/hub.c:5998 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