INFO: task kworker/0:4:4230 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:21392 pid: 4230 ppid: 2 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85 __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x48/0x60 kernel/sched/completion.c:138 flush_workqueue+0x667/0x1390 kernel/workqueue.c:2882 hif_detach_htc drivers/net/wireless/ath/ath6kl/usb.c:861 [inline] ath6kl_usb_power_off+0x34/0x40 drivers/net/wireless/ath/ath6kl/usb.c:1060 ath6kl_hif_power_off drivers/net/wireless/ath/ath6kl/hif-ops.h:143 [inline] ath6kl_core_init+0xac4/0x10a0 drivers/net/wireless/ath/ath6kl/core.c:257 ath6kl_usb_probe+0x1301/0x1410 drivers/net/wireless/ath/ath6kl/usb.c:1160 usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x276/0xc70 drivers/base/dd.c:595 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:775 driver_probe_device+0x4f/0x420 drivers/base/dd.c:805 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429 __device_attach+0x2a7/0x480 drivers/base/dd.c:999 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489 device_add+0xbcf/0x1050 drivers/base/core.c:3427 usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223 usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238 usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x276/0xc70 drivers/base/dd.c:595 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:775 driver_probe_device+0x4f/0x420 drivers/base/dd.c:805 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429 __device_attach+0x2a7/0x480 drivers/base/dd.c:999 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489 device_add+0xbcf/0x1050 drivers/base/core.c:3427 usb_new_device+0x9f6/0x15d0 drivers/usb/core/hub.c:2632 hub_port_connect drivers/usb/core/hub.c:5497 [inline] hub_port_connect_change drivers/usb/core/hub.c:5637 [inline] port_event drivers/usb/core/hub.c:5799 [inline] hub_event+0x2b8d/0x5260 drivers/usb/core/hub.c:5881 process_one_work+0x867/0xff0 kernel/workqueue.c:2310 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 INFO: task kworker/0:5:4231 blocked for more than 145 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:5 state:D stack:22384 pid: 4231 ppid: 2 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85 __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x48/0x60 kernel/sched/completion.c:138 flush_workqueue+0x667/0x1390 kernel/workqueue.c:2882 hif_detach_htc drivers/net/wireless/ath/ath6kl/usb.c:861 [inline] ath6kl_usb_power_off+0x34/0x40 drivers/net/wireless/ath/ath6kl/usb.c:1060 ath6kl_hif_power_off drivers/net/wireless/ath/ath6kl/hif-ops.h:143 [inline] ath6kl_core_init+0xac4/0x10a0 drivers/net/wireless/ath/ath6kl/core.c:257 ath6kl_usb_probe+0x1301/0x1410 drivers/net/wireless/ath/ath6kl/usb.c:1160 usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x276/0xc70 drivers/base/dd.c:595 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:775 driver_probe_device+0x4f/0x420 drivers/base/dd.c:805 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429 __device_attach+0x2a7/0x480 drivers/base/dd.c:999 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489 device_add+0xbcf/0x1050 drivers/base/core.c:3427 usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223 usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238 usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x276/0xc70 drivers/base/dd.c:595 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:775 driver_probe_device+0x4f/0x420 drivers/base/dd.c:805 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429 __device_attach+0x2a7/0x480 drivers/base/dd.c:999 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489 device_add+0xbcf/0x1050 drivers/base/core.c:3427 usb_new_device+0x9f6/0x15d0 drivers/usb/core/hub.c:2632 hub_port_connect drivers/usb/core/hub.c:5497 [inline] hub_port_connect_change drivers/usb/core/hub.c:5637 [inline] port_event drivers/usb/core/hub.c:5799 [inline] hub_event+0x2b8d/0x5260 drivers/usb/core/hub.c:5881 process_one_work+0x867/0xff0 kernel/workqueue.c:2310 process_scheduled_works kernel/workqueue.c:2373 [inline] worker_thread+0xd93/0x12a0 kernel/workqueue.c:2459 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 INFO: task udevd:4330 blocked for more than 145 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:23280 pid: 4330 ppid: 3561 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 device_lock include/linux/device.h:809 [inline] uevent_show+0x16c/0x320 drivers/base/core.c:2408 dev_attr_show+0x50/0xb0 drivers/base/core.c:2110 sysfs_kf_seq_show+0x316/0x4c0 fs/sysfs/file.c:61 seq_read_iter+0x460/0xc50 fs/seq_file.c:230 call_read_iter include/linux/fs.h:2167 [inline] new_sync_read fs/read_write.c:404 [inline] vfs_read+0x75e/0xd50 fs/read_write.c:485 ksys_read+0x153/0x260 fs/read_write.c:623 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fd76972a407 RSP: 002b:00007ffdeb2337f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fd76963c880 RCX: 00007fd76972a407 RDX: 0000000000001000 RSI: 00005607eb8faa00 RDI: 0000000000000008 RBP: 00007fd769872ff0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a R13: 00007fd769872ea0 R14: 0000000000000000 R15: 00005607eb902ce0 INFO: task udevd:4347 blocked for more than 145 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:25168 pid: 4347 ppid: 3561 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 device_lock include/linux/device.h:809 [inline] uevent_show+0x16c/0x320 drivers/base/core.c:2408 dev_attr_show+0x50/0xb0 drivers/base/core.c:2110 sysfs_kf_seq_show+0x316/0x4c0 fs/sysfs/file.c:61 seq_read_iter+0x460/0xc50 fs/seq_file.c:230 call_read_iter include/linux/fs.h:2167 [inline] new_sync_read fs/read_write.c:404 [inline] vfs_read+0x75e/0xd50 fs/read_write.c:485 ksys_read+0x153/0x260 fs/read_write.c:623 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fd76972a407 RSP: 002b:00007ffdeb232620 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fd76963c880 RCX: 00007fd76972a407 RDX: 0000000000001000 RSI: 00005607eb8faa00 RDI: 0000000000000008 RBP: 00007fd769872ff0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a R13: 00007fd769872ea0 R14: 0000000000000000 R15: 00005607eb902ce0 Showing all locks held in the system: 3 locks held by kworker/u4:0/9: 1 lock held by khungtaskd/27: #0: ffffffff8c31ef20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 2 locks held by kworker/0:2/1108: #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc90004657d00 ((work_completion)(&m->mpeg_thread)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 2 locks held by getty/3949: #0: ffff88814cd4a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158 5 locks held by kworker/0:4/4230: #0: ffff88801bda0938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc9000319fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffff8880242c8220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #2: ffff8880242c8220 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5260 drivers/usb/core/hub.c:5827 #3: ffff88801ee50220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #3: ffff88801ee50220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:974 #4: ffff88802123c1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #4: ffff88802123c1a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:974 5 locks held by kworker/0:5/4231: #0: ffff88801bda0938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc900031afd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffff888024298220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #2: ffff888024298220 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5260 drivers/usb/core/hub.c:5827 #3: ffff888075cb4220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #3: ffff888075cb4220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:974 #4: ffff88801fc2f1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #4: ffff88801fc2f1a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:974 4 locks held by udevd/4330: #0: ffff888047b8a9e0 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182 #1: ffff88805fb11888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:112 #2: ffff888062738748 (kn->active#32){++++}-{0:0}, at: kernfs_seq_start+0x75/0x3c0 fs/kernfs/file.c:113 #3: ffff88802123c1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #3: ffff88802123c1a8 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2408 4 locks held by udevd/4347: #0: ffff888025eac540 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182 #1: ffff88805f1b5888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:112 #2: ffff8880240bebd0 (kn->active#32){++++}-{0:0}, at: kernfs_seq_start+0x75/0x3c0 fs/kernfs/file.c:113 #3: ffff888024298220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #3: ffff888024298220 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2408 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe1b/0xe60 kernel/hung_task.c:369 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 144 Comm: kworker/u4:1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: 0x0 (events_unbound) RIP: 0010:hlock_class kernel/locking/lockdep.c:197 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4711 [inline] RIP: 0010:__lock_acquire+0x928/0x7b50 kernel/locking/lockdep.c:4962 Code: 89 c6 41 81 e6 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 c0 b0 1c 90 be 08 00 00 00 e8 f0 2d 61 00 4c 0f a3 35 48 ca bf 0e <73> 1a 4b 8d 04 76 c1 e0 06 4c 8d b0 80 2f b5 8f 49 b8 00 00 00 00 RSP: 0018:ffffc9000173f7c0 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff815ce670 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901cb0c0 RBP: ffffc9000173f9f0 R08: ffffffff901cb0c7 R09: 1ffffffff2039618 R10: dffffc0000000000 R11: fffffbfff2039619 R12: ffff88801bdf28d0 R13: ffff88801bdf1d04 R14: 0000000000000039 R15: ffff88801bdf28d0 FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3fa7f6e2f8 CR3: 000000007e735000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162 debug_object_deactivate+0x63/0x380 lib/debugobjects.c:749 debug_work_deactivate kernel/workqueue.c:514 [inline] process_one_work+0x323/0xff0 kernel/workqueue.c:2240 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287