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:24168 pid:9 tgid:9 ppid:2 task_flags:0x4288060 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x12fc/0x3b90 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115 rwsem_down_read_slowpath+0x64e/0xbf0 kernel/locking/rwsem.c:1086 __down_read_common kernel/locking/rwsem.c:1261 [inline] __down_read kernel/locking/rwsem.c:1274 [inline] down_read+0xef/0x480 kernel/locking/rwsem.c:1539 kernfs_find_and_get_ns+0x2f/0x70 fs/kernfs/dir.c:933 kernfs_find_and_get include/linux/kernfs.h:612 [inline] sysfs_unmerge_group+0x61/0x170 fs/sysfs/group.c:399 dpm_sysfs_remove+0x8e/0xb0 drivers/base/power/sysfs.c:833 device_del+0x1a0/0x9f0 drivers/base/core.c:3853 device_unregister+0x1d/0xc0 drivers/base/core.c:3919 usb_remove_ep_devs+0x42/0x80 drivers/usb/core/endpoint.c:189 remove_intf_ep_devs drivers/usb/core/message.c:1266 [inline] usb_disable_device+0x309/0x7d0 drivers/usb/core/message.c:1417 usb_disconnect+0x2e1/0x9c0 drivers/usb/core/hub.c:2344 hub_port_connect drivers/usb/core/hub.c:5406 [inline] hub_port_connect_change drivers/usb/core/hub.c:5706 [inline] port_event drivers/usb/core/hub.c:5870 [inline] hub_event+0x1aa2/0x5060 drivers/usb/core/hub.c:5952 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5b6/0x6c0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 6 locks held by kworker/0:0/9: #0: ffff888102abe948 ((wq_completion)usb_hub_wq ){+.+.}-{0:0} , at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc9000009fd10 ( (work_completion)(&hub->events) ){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88810b727198 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5898 #3: ffff888118957198 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: usb_disconnect+0x10a/0x9c0 drivers/usb/core/hub.c:2335 #4: ffff88811980d160 ( &dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: __device_driver_lock drivers/base/dd.c:1096 [inline] , at: device_release_driver_internal+0xa4/0x620 drivers/base/dd.c:1294 #5: ffffffff8a02b3e8 ( input_mutex){+.+.}-{4:4} , at: class_mutex_constructor include/linux/mutex.h:228 [inline] , at: __input_unregister_device+0x184/0x4d0 drivers/input/input.c:2221 5 locks held by kworker/0:1/10: 8 locks held by kworker/1:0/23: 1 lock held by khungtaskd/30: #0: ffffffff892c7360 (rcu_read_lock ){....}-{1:3} , at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] , at: rcu_read_lock include/linux/rcupdate.h:841 [inline] , at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:5/310: #0: ffff888100ac4148 ( (wq_completion)netns ){+.+.}-{0:0} , at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900015dfd10 ( net_cleanup_work ){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffffffff8a5e4050 ( pernet_ops_rwsem){++++}-{4:4} , at: cleanup_net+0xad/0x890 net/core/net_namespace.c:658 #3: ffffffff8a5fa288 ( rtnl_mutex ){+.+.}-{4:4} , at: ops_exit_rtnl_list net/core/net_namespace.c:172 [inline] , at: ops_undo_list+0x7e9/0xab0 net/core/net_namespace.c:247 6 locks held by kworker/1:2/1116: 2 locks held by kworker/u8:7/1454: #0: ffff888100089148 ( (wq_completion)events_unbound ){+.+.}-{0:0} , at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90001eafd10 ( (work_completion)(&sub_info->work)){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 2 locks held by getty/2908: #0: ffff88810833e0a0 ( &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 3 locks held by kworker/0:2/3412: #0: ffff888100080d48 ( (wq_completion)events ){+.+.}-{0:0} , at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc9000229fd10 ( free_ipc_work ){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffffffff892d28f8 ( rcu_state.exp_mutex ){+.+.}-{4:4} , at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 6 locks held by kworker/0:3/6116: #0: ffff888102abe948 ( (wq_completion)usb_hub_wq){+.+.}-{0:0} , at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90002927d10 ( (work_completion)(&hub->events)){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88810afe5198 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5898 #3: ffff888117231198 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: usb_disconnect+0x10a/0x9c0 drivers/usb/core/hub.c:2335 #4: ffff88811b0f5160 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: __device_driver_lock drivers/base/dd.c:1096 [inline] , at: device_release_driver_internal+0xa4/0x620 drivers/base/dd.c:1294 #5: ffffffff8a02b3e8 ( input_mutex ){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:228 [inline] ){+.+.}-{4:4}, at: __input_unregister_device+0x184/0x4d0 drivers/input/input.c:2221 3 locks held by kworker/1:3/6130: 5 locks held by kworker/1:5/6149: 1 lock held by udevd/6166: #0: ffffffff892d28f8 ( rcu_state.exp_mutex ){+.+.}-{4:4} , at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by syz-executor.4/7780: #0: ffffffff8a5fa288 ( rtnl_mutex ){+.+.}-{4:4} , at: rtnl_lock net/core/rtnetlink.c:80 [inline] , at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] , at: rtnl_newlink+0x600/0x1e90 net/core/rtnetlink.c:4056 1 lock held by syz-executor.1/7785: #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor.3/7791: #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x600/0x1e90 net/core/rtnetlink.c:4056 1 lock held by syz-executor.2/7817: #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x600/0x1e90 net/core/rtnetlink.c:4056 1 lock held by syz-executor.0/8585: #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor.5/8588: #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor.4/8594: #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor.1/8596: #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor.3/8600: #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor.2/8605: #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8a5fa288 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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:328 [inline] watchdog+0xf0e/0x1260 kernel/hung_task.c:491 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5b6/0x6c0 arch/x86/kernel/process.c:148 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: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: a8 9f 01 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d b3 2e 28 00 fb f4 4c b6 02 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc9000013fdf8 EFLAGS: 000002c2 RAX: 000000000005d2cb RBX: 0000000000000001 RCX: ffffffff873dbcd9 RDX: 0000000000000000 RSI: ffffffff88d27954 RDI: ffffffff878963e0 RBP: ffffed10203d9740 R08: 0000000000000001 R09: ffffed103eb26605 R10: ffff8881f593302b R11: 0000000000000000 R12: 0000000000000001 R13: ffff888101ecba00 R14: ffffffff8a9d73d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888268ff9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4cdb765000 CR3: 0000000116aa0000 CR4: 00000000003506f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:757 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x148