INFO: task kworker/u8:2:36 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/u8:2    state:D
 stack:21208 pid:36    tgid:36    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net

Call Trace:
 <TASK>
 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
 afs_cell_purge+0x40d/0x580 fs/afs/cell.c:921
 afs_net_exit+0x50/0x100 fs/afs/main.c:147
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x49f/0x940 net/core/net_namespace.c:252
 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 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
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:2/36:
 #0: ffff88801be8e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
 #0: ffff88801be8e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
 #1: ffffc90000ac7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
 #1: ffffc90000ac7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
 #2: ffffffff8fdc13e8 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673
2 locks held by getty/5377:
 #0: 
ffff88803201c0a0
 (&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
3 locks held by kworker/1:5/5692:
 #0: ffff8880222f9940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
 #0: ffff8880222f9940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
 #1: ffffc9000440fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
 #1: ffffc9000440fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
 #2: ffff88802a7731d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline]
 #2: ffff88802a7731d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30 drivers/usb/core/hub.c:5899
3 locks held by syz.2.3653/17987:
 #0: ffff888058efa640 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
 #0: ffff888058efa640 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release net/socket.c:721 [inline]
 #0: ffff888058efa640 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1514
 #1: ffff88805518f260 (sk_lock-AF_CAN){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
 #1: ffff88805518f260 (sk_lock-AF_CAN){+.+.}-{0:0}, at: bcm_release+0x1cd/0x940 net/can/bcm.c:1611
 #2: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
 #2: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961

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

NMI backtrace for cpu 1
CPU: 1 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:
 <TASK>
 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+0x388/0x470 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
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5746 Comm: kworker/0:6 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:decay_load kernel/sched/pelt.c:-1 [inline]
RIP: 0010:accumulate_sum kernel/sched/pelt.c:118 [inline]
RIP: 0010:___update_load_sum kernel/sched/pelt.c:227 [inline]
RIP: 0010:update_dl_rq_load_avg+0x1d4/0x980 kernel/sched/pelt.c:375
Code: 89 e7 49 c1 ef 03 41 80 3c 2f 00 74 08 4c 89 e7 e8 61 b8 95 00 49 8b 14 24 49 81 fe 00 80 00 00 0f 83 11 04 00 00 48 8b 34 24 <48> 89 f0 4c 8d 2c 85 20 59 cc 8b 4c 89 e8 48 c1 e8 03 48 bd 00 00
RSP: 0018:ffffc90000007d40 EFLAGS: 00000083
RAX: 0000000000000000 RBX: ffff8880b863ae40 RCX: 0000000000000103
RDX: 0000000000000000 RSI: 0000000000000013 RDI: 000000e34eec9b32
RBP: dffffc0000000000 R08: ffffffff9030b6f7 R09: 1ffffffff20616de
R10: dffffc0000000000 R11: fffffbfff20616df R12: ffff8880b863bad0
R13: 0000000000000000 R14: 0000000000004f26 R15: 1ffff110170c775a
FS:  0000000000000000(0000) GS:ffff88812528d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f74852f0 CR3: 000000007d2b6000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 update_other_load_avgs+0x1e9/0x3e0 kernel/sched/pelt.c:487
 __update_blocked_others kernel/sched/fair.c:10116 [inline]
 __sched_balance_update_blocked_averages+0x6a/0xf40 kernel/sched/fair.c:10240
 sched_balance_update_blocked_averages+0x126/0x2a0 kernel/sched/fair.c:10254
 sched_balance_softirq+0xe1/0x1a0 kernel/sched/fair.c:13349
 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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x7e/0x90 kernel/kcov.c:323
Code: c1 e1 05 4c 8d 51 28 4d 39 ca 77 1e 49 ff c0 4c 89 02 48 c7 44 0a 08 07 00 00 00 48 89 7c 0a 10 48 89 74 0a 18 48 89 44 0a 20 <c3> cc cc cc cc cc 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90
RSP: 0018:ffffc90004d6e4d8 EFLAGS: 00000297
RAX: ffffffff8ba4cf4f RBX: 0000000000000030 RCX: ffff8880278fbd80
RDX: 0000000000000002 RSI: 0000000000000001 RDI: 0000000000000018
RBP: ffffc90004d6e600 R08: ffffc90004d6e577 R09: 0000000000000000
R10: ffffc90004d6e560 R11: fffff520009adcaf R12: ffffc90004d6e8e4
R13: dffffc0000000000 R14: ffffc90004d6e8e4 R15: 0000000000000001
 number+0xbbf/0xf80 lib/vsprintf.c:573
 vsnprintf+0x8e5/0xee0 lib/vsprintf.c:2912
 sprintf+0xe7/0x140 lib/vsprintf.c:3111
 print_time kernel/printk/printk.c:1359 [inline]
 info_print_prefix+0x16b/0x360 kernel/printk/printk.c:1385
 record_print_text+0x176/0x450 kernel/printk/printk.c:1434
 printk_get_next_message+0x29c/0x880 kernel/printk/printk.c:3072
 console_emit_next_record kernel/printk/printk.c:3137 [inline]
 console_flush_one_record kernel/printk/printk.c:3269 [inline]
 console_flush_all+0x501/0xb20 kernel/printk/printk.c:3343
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
 vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
 dev_vprintk_emit+0x355/0x420 drivers/base/core.c:4930
 dev_printk_emit+0xee/0x140 drivers/base/core.c:4941
 _dev_info+0x11e/0x180 drivers/base/core.c:4999
 usb_serial_device_remove+0x153/0x1f0 drivers/usb/serial/bus.c:99
 device_remove drivers/base/dd.c:619 [inline]
 __device_release_driver drivers/base/dd.c:1352 [inline]
 device_release_driver_internal+0x46f/0x870 drivers/base/dd.c:1375
 bus_remove_device+0x455/0x570 drivers/base/bus.c:657
 device_del+0x527/0x8f0 drivers/base/core.c:3895
 usb_serial_disconnect+0x28b/0x4c0 drivers/usb/serial/usb-serial.c:1198
 usb_unbind_interface+0x26e/0x910 drivers/usb/core/driver.c:458
 device_remove drivers/base/dd.c:621 [inline]
 __device_release_driver drivers/base/dd.c:1352 [inline]
 device_release_driver_internal+0x4d9/0x870 drivers/base/dd.c:1375
 bus_remove_device+0x455/0x570 drivers/base/bus.c:657
 device_del+0x527/0x8f0 drivers/base/core.c:3895
 usb_disable_device+0x3d4/0x8d0 drivers/usb/core/message.c:1478
 usb_disconnect+0x32f/0x990 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+0x1cc9/0x4f30 drivers/usb/core/hub.c:5953
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 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
 </TASK>