syzbot

INFO: task kworker/1:2:2651 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:2     state:D stack:21496 pid:2651  tgid:2651  ppid:2      task_flags:0x4288060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x12fc/0x3b80 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
 __mutex_lock_common kernel/locking/mutex.c:676 [inline]
 __mutex_lock+0x818/0x1060 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:12364
 usbnet_disconnect+0x109/0x500 drivers/net/usb/usbnet.c:1660
 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:2345
 hub_port_connect drivers/usb/core/hub.c:5407 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x1aa2/0x5060 drivers/usb/core/hub.c:5953
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x56d/0x700 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
6 locks held by kworker/0:1/10:
 #0: 
ffff8881072d1d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc900000afd10
 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff88810bbf6198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #2: ffff88810bbf6198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5899
 #3: ffff888133ec4198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #3: ffff888133ec4198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #4: ffff88810e712160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #4: ffff88810e712160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #5: ffffffff8a631908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline]
 #5: ffffffff8a631908 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x50 net/core/dev.c:11407
1 lock held by khungtaskd/30:
 #0: ffffffff892c89e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff892c89e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff892c89e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
6 locks held by kworker/1:2/2651:
 #0: ffff8881072d1d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc90003bffd10 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: 
ffff88810b3c9198
 (&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:914 [inline]
, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5899
 #3: ffff88811d5ba198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #3: ffff88811d5ba198 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9c0 drivers/usb/core/hub.c:2336
 #4: ffff888112de4160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #4: ffff888112de4160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1096 [inline]
 #4: ffff888112de4160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xa4/0x620 drivers/base/dd.c:1294
 #5: ffffffff8a631908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #5: ffffffff8a631908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x146/0x360 net/core/dev.c:2142
1 lock held by dhcpcd/2894:
2 locks held by getty/2919:
 #0: ffff88811233b0a0 (&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
6 locks held by kworker/0:6/5488:
 #0: ffff8881072d1d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc90003f0fd10 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff88810b3b1198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #2: ffff88810b3b1198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5899
 #3: ffff888114554198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #3: ffff888114554198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #4: ffff8881183c3160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #4: ffff8881183c3160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #5: ffffffff8a631908 (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:11407
2 locks held by kworker/0:7/5489:
 #0: ffff888100071948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc90003f1fd10 (free_ipc_work){+.+.}-{0:0}
, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
4 locks held by udevd/9164:
 #0: ffff88814482a1c8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12d0 fs/seq_file.c:182
 #1: ffff8881372aec88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
 #2: ffff88812e3920f8 (kn->active#9){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff88812e3920f8 (kn->active#9){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
 #3: ffff888133ec4198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline]
 #3: ffff888133ec4198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
4 locks held by udevd/10681:
 #0: ffff888132980540 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12d0 fs/seq_file.c:182
 #1: ffff88812d1c9088 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
 #2: ffff88812c483e18 (kn->active#9){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff88812c483e18 (kn->active#9){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
 #3: ffff888114554198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline]
 #3: ffff888114554198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
6 locks held by kworker/0:4/16232:
 #0: ffff8881072d1d48
 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc9000f227d10 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff88810b368198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #2: ffff88810b368198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5899
 #3: ffff88811ffe2198 (&dev->mutex
){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #4: ffff888108e9b160
 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #5: ffffffff8a631908 (
rtnl_mutex
){+.+.}-{4:4}
, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline]
, at: register_netdev+0x18/0x50 net/core/dev.c:11407
3 locks held by kworker/u8:1/30825:
 #0: ffff888111b2a948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc9000ea27d10 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)
){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffffffff8a631908
 (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
6 locks held by kworker/1:5/848:
 #0: ffff8881072d1d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: 
ffffc90006447d10
 ((work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff88810b719198
 (
&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5899
 #3: 
ffff88813208f198 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:914 [inline]
, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #4: ffff888128b35160 (&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:914 [inline]
, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #5: ffffffff8a631908
 (rtnl_mutex
){+.+.}-{4:4}
, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline]
, at: register_netdev+0x18/0x50 net/core/dev.c:11407
4 locks held by kworker/u8:3/3842:
 #0: ffff888100ac4948
 ((wq_completion)netns){+.+.}-{0:0}
, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc9000758fd10
 (net_cleanup_work
){+.+.}-{0:0}
, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: 
ffffffff8a61b5b0
 (pernet_ops_rwsem){++++}-{4:4}
, at: cleanup_net+0xad/0x8b0 net/core/net_namespace.c:669
 #3: ffffffff8a631908 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline]
 #3: ffffffff8a631908 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7e9/0xab0 net/core/net_namespace.c:248
1 lock held by syz.1.6663/4306:
 #0: ffffffff892d3f78
 (rcu_state.exp_mutex
){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343

=============================================

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 10/25/2025
Call Trace:
 <TASK>
 __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:332 [inline]
 watchdog+0xf3f/0x1170 kernel/hung_task.c:495
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x56d/0x700 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 2894 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:io_serial_in+0x87/0xb0 drivers/tty/serial/8250/8250_port.c:401
Code: 8b a0 fe 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 1a 66 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c e9 cd ab 69 04 e8 38 c4 00 ff eb a2 e8 c1 c4
RSP: 0018:ffffc9000161ef08 EFLAGS: 00000006
RAX: dffffc0000000005 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: ffffffff82ddc2e0 RDI: ffffffff93bdc700
RBP: ffffffff93bdc6c0 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffffffff93bdc710 R14: ffffffff93bdc6c0 R15: ffffffff93bdc980
FS:  00007f97120d5740(0000) GS:ffff888268ea0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562dfa307af8 CR3: 0000000115764000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 serial_port_in include/linux/serial_core.h:806 [inline]
 serial8250_console_write+0x249/0x1890 drivers/tty/serial/8250/8250_port.c:3306
 console_emit_next_record kernel/printk/printk.c:3111 [inline]
 console_flush_all+0x801/0xc60 kernel/printk/printk.c:3199
 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
 console_unlock+0xd8/0x210 kernel/printk/printk.c:3298
 vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423
 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:12716
 netdev_warn+0xe4/0x120 net/core/dev.c:12769
 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:1149
 usbnet_open+0xcf/0xbe0 drivers/net/usb/usbnet.c:912
 __dev_open+0x3a3/0x850 net/core/dev.c:1682
 __dev_change_flags+0x55d/0x720 net/core/dev.c:9637
 netif_change_flags+0x8d/0x160 net/core/dev.c:9700
 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:1003
 sock_do_ioctl+0x118/0x280 net/socket.c:1254
 sock_ioctl+0x42f/0x6a0 net/socket.c:1375
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 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: 0033:0x7f97121d5378
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:00007ffe75622778 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f97121d5378
RDX: 00007ffe75632970 RSI: 0000000000008914 RDI: 0000000000000008
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe75642b10
R13: 00007f97120d56c8 R14: 0000000000000028 R15: 0000000000008914
 </TASK>