INFO: task kworker/0:7:6945 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:7 state:D stack:21864 pid:6945 tgid:6945 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 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x82a/0x10b0 kernel/locking/mutex.c:760 rtnl_net_lock include/linux/rtnetlink.h:130 [inline] rtnl_net_dev_lock+0x146/0x360 net/core/dev.c:2142 unregister_netdev+0x15/0x60 net/core/dev.c:12228 usbnet_disconnect+0x109/0x500 drivers/net/usb/usbnet.c:1658 usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:458 device_remove drivers/base/dd.c:571 [inline] device_remove+0x125/0x170 drivers/base/dd.c:563 __device_release_driver drivers/base/dd.c:1274 [inline] device_release_driver_internal+0x44b/0x620 drivers/base/dd.c:1297 bus_remove_device+0x22f/0x420 drivers/base/bus.c:579 device_del+0x396/0x9f0 drivers/base/core.c:3878 usb_disable_device+0x355/0x7d0 drivers/usb/core/message.c:1418 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+0x9cf/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 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: ffff88810729e148 ((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: ffff88810b798198 ( &dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] &dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5898 #3: ffff88811c8ab198 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #4: ffff888139705160 ( &dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] &dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #5: ffffffff8a5f9588 (rtnl_mutex ){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline] ){+.+.}-{4:4}, at: register_netdev+0x18/0x50 net/core/dev.c:11302 6 locks held by kworker/0:1/10: #0: ffff88810729e148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900000afd10 ((work_completion)(&hub->events)){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88810b708198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] ffff88810b708198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5898 #3: ffff888118409198 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #4: ffff888119a8a160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #5: ffffffff8a5f9588 (rtnl_mutex ){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline] ){+.+.}-{4:4}, at: register_netdev+0x18/0x50 net/core/dev.c:11302 1 lock held by khungtaskd/30: #0: ffffffff892c7320 ( rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 5 locks held by kworker/1:1/42: #0: ffff88810729e148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900002c7d10 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88810af53198 ( &dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] &dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5898 #3: ffff888123af4198 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #4: ffff88811033a160 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 3 locks held by kworker/u8:6/1113: #0: ffff888111ab4948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90001c7fd10 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffffffff8a5f9588 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8a5f9588 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4734 1 lock held by dhcpcd/2884: 2 locks held by getty/2907: #0: ffff8881124b70a0 (&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 4 locks held by udevd/5171: #0: ffff88811ec36b08 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 #1: ffff88811d4b0c88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 #2: ffff88811b5cfe18 (kn->active#9){++++}-{0:0} , at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155 #3: ffff888118409198 (&dev->mutex ){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:916 [inline] ){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 4 locks held by udevd/5345: #0: ffff8881359a41c8 (&p->lock ){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 #1: ffff88811df44c88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 #2: ffff888135aa80f8 (kn->active#12){.+.+}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155 #3: ffff88811c8ab198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:916 [inline] #3: ffff88811c8ab198 (&dev->mutex){....}-{4:4}, at: serial_show+0x26/0xa0 drivers/usb/core/sysfs.c:143 6 locks held by kworker/0:7/6945: #0: ffff88810729e148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90015ac7d10 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88810b3f8198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5898 #3: ffff88813a518198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9c0 drivers/usb/core/hub.c:2335 #4: ffff888111314160 (&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: ffffffff8a5f9588 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x146/0x360 net/core/dev.c:2142 6 locks held by kworker/1:9/9849: #0: ffff88810729e148 ((wq_completion)usb_hub_wq ){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90001b8fd10 ((work_completion)(&hub->events) ){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88810b3d8198 (&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: ffff888114dbe198 ( &dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #4: ffff88810ebe2160 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #5: ffffffff8a5f9588 ( rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline] rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x50 net/core/dev.c:11302 ============================================= 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+0x3c2/0x780 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: 5223 Comm: kworker/1:4 Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: events dvb_usb_read_remote_control RIP: 0010:in_softirq_really kernel/kcov.c:171 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x23/0x70 kernel/kcov.c:217 Code: 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 34 24 65 48 8b 15 48 41 14 0b 65 8b 05 59 41 14 0b a9 00 01 ff 00 74 1d f6 c4 01 74 43 00 00 0f 00 75 3c a9 00 00 f0 00 75 35 8b 82 74 15 00 00 85 c0 RSP: 0018:ffffc900001a8f18 EFLAGS: 00000202 RAX: 0000000000000101 RBX: 0000000000000002 RCX: ffffffff8142b848 RDX: ffff8881225aba00 RSI: ffffffff816a7f89 RDI: ffffffff88dd3be8 RBP: 0000000000000001 R08: 0000000000000000 R09: fffffbfff153acba R10: ffffffff8a9d65d7 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000101 R14: 0000000000000001 R15: ffffffff8900c0c8 FS: 0000000000000000(0000) GS:ffff888268ffc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f95a13a3000 CR3: 000000011cfde000 CR4: 00000000003506f0 Call Trace: run_timer_softirq+0x9/0x40 kernel/time/timer.c:2401 handle_softirqs+0x208/0x8d0 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xfa/0x160 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2061 [inline] RIP: 0010:vprintk_emit+0x567/0x6d0 kernel/printk/printk.c:2449 Code: 00 4d 85 ed 0f 85 19 01 00 00 e8 74 80 20 00 9c 5d 81 e5 00 02 00 00 31 ff 48 89 ee e8 d2 7b 20 00 48 85 ed 0f 85 25 01 00 00 54 80 20 00 45 31 c9 41 b8 01 00 00 00 31 c9 48 8d 05 00 00 00 RSP: 0018:ffffc900020ffac8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 000000000000003e RCX: ffffffff815d7f7c RDX: ffff8881225aba00 RSI: ffffffff815d7f86 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff9200041ff5b R13: 0000000000000200 R14: ffff888102685700 R15: ffffc900020ffb90 _printk+0xc7/0x100 kernel/printk/printk.c:2475 dvb_usb_read_remote_control+0x174/0x1c0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:263 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 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