syzbot

INFO: task kworker/0:4:5224 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:4     state:D stack:21656 pid:5224  tgid:5224  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>
INFO: task kworker/u8:2:16853 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:2    state:D stack:26152 pid:16853 tgid:16853 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: ipv6_addrconf addrconf_verify_work
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]
 addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4734
 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:
1 lock held by khungtaskd/30:
 #0: ffffffff892c89e0
 (rcu_read_lock
){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
4 locks held by dhcpcd/2893:
2 locks held by getty/2916:
 #0: 
ffff8881157380a0 (&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/1:3/5218:
 #0: ffff8881072a6948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: 
ffffc9000202fd10 ((work_completion)(&hub->events)){+.+.}-{0:0}
, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: 
ffff88810bb63198 (&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: 
ffff888123108198 (&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:914 [inline]
, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #4: ffff8881326c6160 (&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:914 [inline]
, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #5: ffffffff8a631a48 (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 udevd/5221:
 #0: 
ffff888113541540
 (&p->lock
){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12d0 fs/seq_file.c:182
 #1: 
ffff888137334488
 (&of->mutex
#2
){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
 #2: ffff888133f1bd28 (kn->active
#9){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#9){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
 #3: ffff888132810198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline]
 #3: ffff888132810198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
6 locks held by kworker/0:4/5224:
 #0: 
ffff8881072a6948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc9000207fd10
 ((work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff88810b776198 (&dev->mutex
){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5899
 #3: ffff88811b4f5198
 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9c0 drivers/usb/core/hub.c:2336
 #4: ffff888138158160 (&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:914 [inline]
, at: __device_driver_lock drivers/base/dd.c:1096 [inline]
, at: device_release_driver_internal+0xa4/0x620 drivers/base/dd.c:1294
 #5: ffffffff8a631a48
 (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:2142
6 locks held by kworker/1:7/5729:
 #0: ffff8881072a6948
 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc900125bfd10
 (
(work_completion)(&hub->events)
){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff88810b756198
 (
&dev->mutex
){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5899
 #3: ffff888130e83198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #3: ffff888130e83198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #4: 
ffff888120fba160
 (&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:914 [inline]
, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #5: 
ffffffff8a631a48
 (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
6 locks held by kworker/1:9/6559:
 #0: ffff8881072a6948
 ((wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: 
ffffc90013d87d10
 (
(work_completion)(&hub->events)
){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff88810974e198
 (
&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: ffff88812ffd4198
 (&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
 #4: ffff888138ca4160 (
&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:914 [inline]
, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #5: ffffffff8a631a48
 (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
6 locks held by kworker/1:2/13518:
 #0: ffff8881072a6948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: 
ffffc9001500fd10 (
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff88810b7f1198
 (&dev->mutex
){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5899
 #3: ffff888132810198
 (&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
 #4: ffff888113c9a160 (&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
 #5: ffffffff8a631a48
 (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
3 locks held by kworker/u8:2/16853:
 #0: ffff88811220b148
 ((wq_completion)ipv6_addrconf
){+.+.}-{0:0}
, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: 
ffffc9001722fd10
 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)
){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffffffff8a631a48
 (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 syz.1.3738/20675:

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

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 10/02/2025
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 20523 Comm: kworker/1:11 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: events legacy_dvb_usb_read_remote_control
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:158 [inline]
RIP: 0010:lock_is_held_type+0xf8/0x150 kernel/locking/lockdep.c:5942
Code: f0 41 0f 94 c5 48 c7 c7 b8 84 c6 88 e8 f1 13 00 00 b8 ff ff ff ff 65 0f c1 05 ac 8d 53 05 83 f8 01 75 2d 9c 58 f6 c4 02 75 43 <48> f7 04 24 00 02 00 00 74 01 fb 48 83 c4 08 44 89 e8 5b 5d 41 5c
RSP: 0018:ffffc900001a8c38 EFLAGS: 00000046
RAX: 0000000000000046 RBX: ffff88813780c4f8 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff88c684b8 RDI: ffffffff878979c0
RBP: ffff8881f5938918 R08: 0000000000000000 R09: fffffbfff1541d7a
R10: ffffffff8aa0ebd7 R11: 0000000000000001 R12: ffff88813780ba00
R13: 0000000000000001 R14: 00000000ffffffff R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff888268fa0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7b3afded58 CR3: 000000013ad82000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 lock_is_held include/linux/lockdep.h:249 [inline]
 lockdep_assert_rq_held kernel/sched/sched.h:1537 [inline]
 rq_clock_pelt kernel/sched/pelt.h:71 [inline]
 cfs_rq_clock_pelt kernel/sched/pelt.h:185 [inline]
 update_load_avg+0xda5/0x2010 kernel/sched/fair.c:4718
 entity_tick kernel/sched/fair.c:5572 [inline]
 task_tick_fair+0x8d/0x3b0 kernel/sched/fair.c:13124
 sched_tick+0x209/0x710 kernel/sched/core.c:5600
 update_process_times+0x19c/0x2d0 kernel/time/timer.c:2478
 tick_sched_handle kernel/time/tick-sched.c:276 [inline]
 tick_nohz_handler+0x37e/0x540 kernel/time/tick-sched.c:297
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x5ed/0xad0 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1058
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0x8b/0xb0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2034 [inline]
RIP: 0010:vprintk_emit+0x526/0x680 kernel/printk/printk.c:2422
Code: 00 4d 85 ed 0f 85 19 01 00 00 e8 a5 9d 20 00 9c 5d 81 e5 00 02 00 00 31 ff 48 89 ee e8 03 99 20 00 48 85 ed 0f 85 25 01 00 00 <e8> 85 9d 20 00 45 31 c9 41 b8 01 00 00 00 31 c9 48 8d 05 00 00 00
RSP: 0018:ffffc90001b5fa38 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 000000000000003a RCX: ffffffff815db1eb
RDX: ffff88813780ba00 RSI: ffffffff815db1f5 RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 1ffff9200036bf49
R13: 0000000000000200 R14: ffff888101eed700 R15: ffffc90001b5fb00
 _printk+0xc7/0x100 kernel/printk/printk.c:2448
 legacy_dvb_usb_read_remote_control+0x40b/0x4f0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:124
 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>