BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 150s! BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=-20 stuck for 148s! Showing busy workqueues and worker pools: workqueue events: flags=0x100 pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2 in-flight: 2804:request_firmware_work_func pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2 pending: free_obj_work workqueue events_power_efficient: flags=0x180 pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=5 refcnt=6 pending: 5*check_lifetime workqueue mm_percpu_wq: flags=0x8 pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2 pending: vmstat_update workqueue kblockd: flags=0x18 pwq 7: cpus=1 node=0 flags=0x0 nice=-20 active=2 refcnt=3 pending: blk_mq_requeue_work, blk_mq_timeout_work workqueue usb_hub_wq: flags=0x104 pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=6 refcnt=7 in-flight: 5225:hub_event hub_event ,5224:hub_event hub_event ,10:hub_event hub_event pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=4 refcnt=5 in-flight: 5260:hub_event hub_event ,1120:hub_event hub_event pool 2: cpus=0 node=0 flags=0x0 nice=0 hung=0s workers=7 idle: 9 5294 5223 pool 6: cpus=1 node=0 flags=0x0 nice=0 hung=150s workers=6 idle: 42 5230 5261 23 Showing backtraces of running workers in stalled CPU-bound worker pools: pool 6: task:kworker/1:4 state:R running task stack:21608 pid:5260 tgid:5260 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x145d/0x4a00 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 msleep+0x32/0x50 kernel/time/sleep_timeout.c:318 hub_port_init+0x7fe/0x3bb0 drivers/usb/core/hub.c:5032 hub_port_connect drivers/usb/core/hub.c:5496 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x2f75/0x5420 drivers/usb/core/hub.c:5953 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x74f/0xa30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 pool 6: task:kworker/1:2 state:R running task stack:22048 pid:1120 tgid:1120 ppid:2 task_flags:0x4208060 flags:0x00080010 Workqueue: usb_hub_wq hub_event Call Trace: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5224 Comm: kworker/0:4 Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: usb_hub_wq hub_event RIP: 0010:__rb_erase_augmented include/linux/rbtree_augmented.h:259 [inline] RIP: 0010:rb_erase+0x89/0x1370 lib/rbtree.c:443 Code: 85 ff 0f 84 90 05 00 00 4d 85 f6 0f 84 3a 07 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d 7e 10 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 8d 0c 00 00 49 8b 5e 10 4c 89 f5 48 ba 00 00 00 00 00 fc ff RSP: 0018:ffffc90000007ac8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff8881f5639a88 RCX: ffff8881f5628190 RDX: 1ffff92000283fb1 RSI: ffff8881f5628190 RDI: ffffc9000141fd88 RBP: ffff8881f5628190 R08: 0000000000000006 R09: 0000000000000001 R10: ffff8881f5639a88 R11: ffff8881136a8aa8 R12: ffff8881f5628198 R13: ffff8881f5639a88 R14: ffffc9000141fd78 R15: ffffc9000183fd78 FS: 0000000000000000(0000) GS:ffff888268bf5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc8f720b68 CR3: 00000001263fa000 CR4: 00000000003506f0 Call Trace: rb_erase_cached include/linux/rbtree.h:154 [inline] timerqueue_del+0x83/0x150 lib/timerqueue.c:57 __remove_hrtimer+0x99/0x290 kernel/time/hrtimer.c:1114 remove_hrtimer kernel/time/hrtimer.c:1163 [inline] hrtimer_try_to_cancel+0x2a1/0x4d0 kernel/time/hrtimer.c:1358 update_curr_dl_se+0x50d/0xd00 kernel/sched/deadline.c:1487 update_curr+0x397/0x570 kernel/sched/fair.c:1227 enqueue_entity kernel/sched/fair.c:5228 [inline] enqueue_task_fair+0x2b7/0x21f0 kernel/sched/fair.c:6932 enqueue_task+0xd0/0x270 kernel/sched/core.c:2094 activate_task kernel/sched/core.c:2135 [inline] ttwu_do_activate+0x12e/0x890 kernel/sched/core.c:3631 ttwu_queue kernel/sched/core.c:3894 [inline] try_to_wake_up+0x72d/0x1480 kernel/sched/core.c:4218 hrtimer_wakeup+0x47/0x60 kernel/time/hrtimer.c:2013 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x202/0xc40 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3c0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x8b/0xb0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2037 [inline] RIP: 0010:vprintk_emit+0x556/0x6b0 kernel/printk/printk.c:2425 Code: 00 4d 85 ed 0f 85 19 01 00 00 e8 85 1d 21 00 9c 5d 81 e5 00 02 00 00 31 ff 48 89 ee e8 43 18 21 00 48 85 ed 0f 85 25 01 00 00 65 1d 21 00 45 31 c9 41 b8 01 00 00 00 31 c9 48 8d 05 00 00 00 RSP: 0018:ffffc9000227eb78 EFLAGS: 00000283 RAX: 000000000006ac29 RBX: 0000000000000033 RCX: ffffc9000fbc8000 RDX: 0000000000100000 RSI: ffffffff815ed025 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: ffff8881136a8aa8 R12: 1ffff9200044fd71 R13: 0000000000000200 R14: ffff88810eb5ba80 R15: ffffc9000227ec40 dev_vprintk_emit drivers/base/core.c:4914 [inline] dev_printk_emit+0xfa/0x140 drivers/base/core.c:4925 __netdev_printk+0x1ff/0x480 net/core/dev.c:12901 netdev_err+0xe4/0x120 net/core/dev.c:12953 pcan_usb_fd_send_cmd+0x2bf/0x390 drivers/net/can/usb/peak_usb/pcan_usb_fd.c:231 pcan_usb_fd_set_clock_domain drivers/net/can/usb/peak_usb/pcan_usb_fd.c:415 [inline] pcan_usb_fd_init+0x6bc/0x1350 drivers/net/can/usb/peak_usb/pcan_usb_fd.c:1044 peak_usb_create_dev drivers/net/can/usb/peak_usb/pcan_usb_core.c:997 [inline] peak_usb_probe+0x9a0/0xfb0 drivers/net/can/usb/peak_usb/pcan_usb_core.c:1085 usb_probe_interface+0x303/0xa80 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:581 [inline] really_probe+0x241/0xb20 drivers/base/dd.c:659 __driver_probe_device+0x1de/0x470 drivers/base/dd.c:801 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:831 __device_attach_driver+0x1df/0x350 drivers/base/dd.c:959 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4e0 drivers/base/dd.c:1031 device_initial_probe+0xaa/0xc0 drivers/base/dd.c:1086 bus_probe_device+0x64/0x150 drivers/base/bus.c:574 device_add+0x116e/0x1980 drivers/base/core.c:3689 usb_set_configuration+0x1187/0x1e50 drivers/usb/core/message.c:2210 usb_generic_driver_probe+0xb1/0x110 drivers/usb/core/generic.c:250 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291 call_driver_probe drivers/base/dd.c:581 [inline] really_probe+0x241/0xb20 drivers/base/dd.c:659 __driver_probe_device+0x1de/0x470 drivers/base/dd.c:801 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:831 __device_attach_driver+0x1df/0x350 drivers/base/dd.c:959 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4e0 drivers/base/dd.c:1031 device_initial_probe+0xaa/0xc0 drivers/base/dd.c:1086 bus_probe_device+0x64/0x150 drivers/base/bus.c:574 device_add+0x116e/0x1980 drivers/base/core.c:3689 usb_new_device+0xd07/0x1a90 drivers/usb/core/hub.c:2695 hub_port_connect drivers/usb/core/hub.c:5567 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x31bf/0x5420 drivers/usb/core/hub.c:5953 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x74f/0xa30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 ---------------- Code disassembly (best guess): 0: 85 ff test %edi,%edi 2: 0f 84 90 05 00 00 je 0x598 8: 4d 85 f6 test %r14,%r14 b: 0f 84 3a 07 00 00 je 0x74b 11: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 18: fc ff df 1b: 49 8d 7e 10 lea 0x10(%r14),%rdi 1f: 48 89 fa mov %rdi,%rdx 22: 48 c1 ea 03 shr $0x3,%rdx 26: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) * 2a: 0f 85 8d 0c 00 00 jne 0xcbd <-- trapping instruction 30: 49 8b 5e 10 mov 0x10(%r14),%rbx 34: 4c 89 f5 mov %r14,%rbp 37: 48 rex.W 38: ba 00 00 00 00 mov $0x0,%edx 3d: 00 fc add %bh,%ah 3f: ff .byte 0xff