INFO: task kworker/0:6:5277 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:6 state:D stack:22312 pid:5277 tgid:5277 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+0x81b/0x1060 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:12246 usbnet_disconnect+0x109/0x500 drivers/net/usb/usbnet.c:1658 usb_unbind_interface+0x1da/0x9e0 drivers/usb/core/driver.c:458 device_remove drivers/base/dd.c:571 [inline] device_remove+0x122/0x170 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+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x56d/0x700 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: 1 lock held by khungtaskd/30: #0: ffffffff892c76e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff892c76e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff892c76e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:7/1684: #0: ffff888111b74148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc9000253fd10 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffffffff8a5fc208 (rtnl_mutex ){+.+.}-{4:4} , at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] , at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4734 1 lock held by dhcpcd/2889: 2 locks held by getty/2912: #0: ffff888109aa70a0 (&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/5194: #0: ffff8881324738b8 (&p->lock){+.+.}-{4:4} , at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 #1: ffff88811be61c88 (&of->mutex#2){+.+.}-{4:4} , at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888116e2c968 (kn->active #18){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #18){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff888106efd198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:916 [inline] (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 6 locks held by kworker/0:4/5220: #0: ffff888106eaf948 ((wq_completion)usb_hub_wq){+.+.}-{0:0} , at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90001fffd10 ((work_completion)(&hub->events) ){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88810b764198 ( &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: ffff888138312198 (&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 #4: ffff88810934d160 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:911 [inline] , at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #5: ffffffff8a5fc208 (rtnl_mutex){+.+.}-{4:4} , at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline] , at: register_netdev+0x18/0x50 net/core/dev.c:11319 4 locks held by udevd/5225: #0: ffff8881180ffc30 (&p->lock ){+.+.}-{4:4} , at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 #1: ffff888116a2d888 ( &of->mutex #2){+.+.}-{4:4} , at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888135ac4c38 (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: ffff888138312198 (&dev->mutex){....}-{4:4} , at: device_lock_interruptible include/linux/device.h:916 [inline] , at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 6 locks held by kworker/0:6/5277: #0: ffff888106eaf948 ( (wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900022efd10 ((work_completion)(&hub->events)){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88810b354198 (&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: ffff88811e2b8198 ( &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: ffff88811eb34160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1096 [inline] (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xa4/0x620 drivers/base/dd.c:1294 #5: ffffffff8a5fc208 ( rtnl_mutex ){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] ){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x146/0x360 net/core/dev.c:2142 6 locks held by kworker/1:6/5362: #0: ffff888106eaf948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90002587d10 ((work_completion)(&hub->events) ){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88810b794198 (&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: ffff88811b59e198 (&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 #4: ffff888119b7d160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] #4: ffff888119b7d160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #5: ffffffff8a5fc208 (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:11319 5 locks held by kworker/1:8/7008: 2 locks held by syz.3.806/8171: ============================================= 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 08/18/2025 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+0x56d/0x700 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 2889 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3288 [inline] RIP: 0010:serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3311 [inline] RIP: 0010:serial8250_console_write+0xf81/0x1890 drivers/tty/serial/8250/8250_port.c:3396 Code: 15 a1 a2 fe 41 83 c4 01 44 89 ef 44 89 e6 e8 86 9b a2 fe 45 39 e5 74 22 e8 fc a0 a2 fe be 20 00 00 00 4c 89 f7 e8 3f a2 fe ff <31> ff 89 c5 89 c6 e8 c4 9b a2 fe 40 84 ed 74 c5 e8 da a0 a2 fe 48 RSP: 0018:ffffc900015fef28 EFLAGS: 00000096 RAX: 0000000000000001 RBX: ffffffff939cb3e0 RCX: ffffffff82d9fddb RDX: ffff88810c2dba00 RSI: ffffffff82d9fde6 RDI: 0000000000000005 RBP: 000000000000002f R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000823 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000010 R14: ffffffff93b871a0 R15: 0000000000000001 FS: 00007f873b4db740(0000) GS:ffff888268ef4000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe6fe30ff8 CR3: 0000000116ba2000 CR4: 00000000003506f0 Call Trace: console_emit_next_record kernel/printk/printk.c:3138 [inline] console_flush_all+0x801/0xc60 kernel/printk/printk.c:3226 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xd8/0x210 kernel/printk/printk.c:3325 vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450 dev_vprintk_emit drivers/base/core.c:4914 [inline] dev_printk_emit+0xfa/0x140 drivers/base/core.c:4925 __netdev_printk+0x1fb/0x500 net/core/dev.c:12598 netdev_warn+0xe4/0x120 net/core/dev.c:12651 asix_write_cmd+0xf1/0x100 drivers/net/usb/asix_common.c:57 asix_set_sw_mii drivers/net/usb/asix_common.c:75 [inline] asix_check_host_enable+0x154/0x240 drivers/net/usb/asix_common.c:98 __asix_mdio_read+0x9c/0x260 drivers/net/usb/asix_common.c:484 asix_phy_reset+0x106/0x1f0 drivers/net/usb/asix_devices.c:215 ax88178_reset+0x42d/0x12f0 drivers/net/usb/asix_devices.c:1125 usbnet_open+0xcc/0xbe0 drivers/net/usb/usbnet.c:910 __dev_open+0x3a3/0x850 net/core/dev.c:1682 __dev_change_flags+0x55d/0x720 net/core/dev.c:9549 netif_change_flags+0x8d/0x160 net/core/dev.c:9612 dev_change_flags+0xb6/0x170 net/core/dev_api.c:68 devinet_ioctl+0x11d5/0x1f50 net/ipv4/devinet.c:1199 inet_ioctl+0x3a7/0x3f0 net/ipv4/af_inet.c:1001 sock_do_ioctl+0x118/0x280 net/socket.c:1238 sock_ioctl+0x42f/0x6a0 net/socket.c:1359 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:598 [inline] __se_sys_ioctl fs/ioctl.c:584 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4d0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f873b5db378 Code: 00 00 48 8d 44 24 08 48 89 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 b8 10 00 00 00 c7 44 24 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 07 89 d0 c3 0f 1f 40 00 48 8b 15 49 3a 0d RSP: 002b:00007fffa8716308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f873b5db378 RDX: 00007fffa8726500 RSI: 0000000000008914 RDI: 0000000000000008 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffa87366a0 R13: 00007f873b4db6c8 R14: 0000000000000028 R15: 0000000000008914