INFO: task kworker/0:4:5728 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:4 state:D stack:20200 pid:5728 tgid:5728 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7f7/0x1550 kernel/locking/mutex.c:820 hub_port_connect drivers/usb/core/hub.c:5465 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x21a2/0x4f30 drivers/usb/core/hub.c:5953 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by ksoftirqd/0/15: 1 lock held by khungtaskd/31: #0: ffffffff8e95cc20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e95cc20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e95cc20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:6/143: #0: ffff8880b863aee0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb6/0x150 kernel/sched/core.c:660 #1: ffffc90002e6fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc90002e6fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffff8880b863aee0 (&rq->__lock){-.-.}-{2:2}, at: finish_lock_switch kernel/sched/core.c:5122 [inline] #2: ffff8880b863aee0 (&rq->__lock){-.-.}-{2:2}, at: finish_task_switch+0x15f/0xbe0 kernel/sched/core.c:5243 1 lock held by udevd/4998: 2 locks held by getty/5386: #0: ffff8880358770a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211 5 locks held by kworker/1:7/5721: #0: ffff8880216f1540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff8880216f1540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc90004b0fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc90004b0fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffff88802b0981d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88802b0981d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30 drivers/usb/core/hub.c:5899 #3: ffff88802b09d568 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff88802b09d568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline] #3: ffff88802b09d568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #3: ffff88802b09d568 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #3: ffff88802b09d568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x217a/0x4f30 drivers/usb/core/hub.c:5953 #4: ffff88801f7b0260 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline] #4: ffff88801f7b0260 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #4: ffff88801f7b0260 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #4: ffff88801f7b0260 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21a2/0x4f30 drivers/usb/core/hub.c:5953 5 locks held by kworker/0:4/5728: #0: ffff8880216f1540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff8880216f1540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc90004b7fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc90004b7fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffff88802b02e1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88802b02e1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30 drivers/usb/core/hub.c:5899 #3: ffff88802b08b568 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff88802b08b568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline] #3: ffff88802b08b568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #3: ffff88802b08b568 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #3: ffff88802b08b568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x217a/0x4f30 drivers/usb/core/hub.c:5953 #4: ffff88801f7b0260 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline] #4: ffff88801f7b0260 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #4: ffff88801f7b0260 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #4: ffff88801f7b0260 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21a2/0x4f30 drivers/usb/core/hub.c:5953 2 locks held by syz.0.1793/12162: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xfd3/0x1030 kernel/hung_task.c:561 kthread+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 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: 4998 Comm: udevd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:write_comp_data kernel/kcov.c:245 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x8/0x90 kernel/kcov.c:321 Code: 89 44 11 20 c3 cc cc cc cc cc 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 78 84 72 11 65 8b 15 99 84 72 11 81 e2 00 01 ff 00 74 RSP: 0018:ffffc90000a08b60 EFLAGS: 00000206 RAX: ffffffff89b5246c RBX: 0019999999999999 RCX: 0000000000000100 RDX: ffff88807d191f00 RSI: 0000000000000000 RDI: 0019999999999999 RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000141170 R12: 00000015798ee228 R13: 0019999999999998 R14: ffff888049a0ea30 R15: 0000000225c17d04 FS: 00007f4489b92880(0000) GS:ffff88812539c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0432141000 CR3: 000000007d29e000 CR4: 00000000003526f0 Call Trace: pie_calculate_probability+0x1dc/0x7e0 net/sched/sch_pie.c:345 fq_pie_timer+0x288/0x5b0 net/sched/sch_fq_pie.c:402 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2374 [inline] __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386 run_timer_base kernel/time/timer.c:2395 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:100 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline] RIP: 0010:unwind_next_frame+0x534/0x2550 arch/x86/kernel/unwind_orc.c:510 Code: 0f b6 04 08 84 c0 75 27 49 63 07 4c 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 49 8d 47 fc 48 0f 47 d8 4d 0f 46 ef 48 39 dd 76 a2 7b fd ff ff 44 89 f9 80 e1 07 80 c1 03 38 c1 7c cc 4c 89 ff 48 RSP: 0018:ffffc9000395f9d8 EFLAGS: 00000202 RAX: ffffffff9053294c RBX: ffffffff90532950 RCX: ffffffff90532954 RDX: ffffffff90532950 RSI: ffffffff90d4185a RDI: ffffffff8c28b880 RBP: ffffffff90532954 R08: 0000000000000009 R09: ffffffff8e95cc20 R10: ffffc9000395faf8 R11: ffffffff81b0e0e0 R12: ffffffff8246e881 R13: ffffffff90532950 R14: ffffc9000395faa8 R15: ffffffff90532950 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6251 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6378 free_filename fs/namei.c:147 [inline] putname fs/namei.c:306 [inline] class_filename_destructor include/linux/fs.h:2553 [inline] __do_sys_unlink fs/namei.c:5604 [inline] __se_sys_unlink+0xc2/0x140 fs/namei.c:5600 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4489515937 Code: 00 00 e9 a9 fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 5f 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 91 b4 0d 00 f7 d8 64 89 02 b8 RSP: 002b:00007fffda781fc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000bb8 RCX: 00007f4489515937 RDX: 0000000000000000 RSI: 000000002489a340 RDI: 000055ae77ab602e RBP: 0000000000000000 R08: 000000002496c209 R09: 3fffffffffffffff R10: 4000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 000055ae77ad1100 R14: 0000000000000001 R15: 0000000000000000