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:20168 pid:36 tgid:36 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x17b4/0x5680 kernel/sched/core.c:7188
__schedule_loop kernel/sched/core.c:7267 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7282
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
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e95cce0 (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: ffff88801be9e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff88801be9e140 ((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: ffffffff8fdd5228 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673
2 locks held by getty/5598:
#0: ffff8880326b40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211
3 locks held by kworker/u9:3/11472:
#0: ffff888056f64140 ((wq_completion)hci1){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff888056f64140 ((wq_completion)hci1){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc90003da7c40 ((work_completion)(&hdev->error_reset)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc90003da7c40 ((work_completion)(&hdev->error_reset)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
#2: ffff888057a80ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_open net/bluetooth/hci_core.c:429 [inline]
#2: ffff888057a80ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_error_reset+0x159/0x4c0 net/bluetooth/hci_core.c:1036
1 lock held by syz.5.3886/18451:
#0: ffffffff8e962eb8 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
1 lock held by syz.6.3891/18466:
=============================================
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+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
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 757 Comm: kworker/u8:7 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: events_unbound nsim_dev_trap_report_work
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:-1 [inline]
RIP: 0010:debug_check_no_obj_freed+0x1f1/0x550 lib/debugobjects.c:1146
Code: 0f 84 44 03 00 00 49 89 ee 49 c1 ee 03 41 80 3c 16 00 74 12 48 89 ef e8 fd cf 74 fd 48 ba 00 00 00 00 00 fc ff df 48 8b 45 00 <48> 89 04 24 4c 8d 7d 18 4c 89 f8 48 c1 e8 03 80 3c 10 00 74 12 4c
RSP: 0018:ffffc90004217850 EFLAGS: 00000046
RAX: ffff888033514070 RBX: 000000000000000e RCX: 0000000000000001
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc900042177c0
RBP: ffff88805dabfd20 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000842ef8 R12: ffff888050a9d000
R13: ffff888050a9c000 R14: 1ffff1100bb57fa4 R15: ffff888054fcb8d8
FS: 0000000000000000(0000) GS:ffff888125313000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555862bca28 CR3: 000000007720c000 CR4: 00000000003526f0
Call Trace:
slab_free_hook mm/slub.c:2620 [inline]
slab_free mm/slub.c:6246 [inline]
kfree+0x13e/0x640 mm/slub.c:6561
skb_kfree_head net/core/skbuff.c:1075 [inline]
skb_free_head net/core/skbuff.c:1087 [inline]
skb_release_data+0x828/0xa60 net/core/skbuff.c:1114
skb_release_all net/core/skbuff.c:1189 [inline]
__kfree_skb+0x5d/0x210 net/core/skbuff.c:1203
nsim_dev_trap_report drivers/net/netdevsim/dev.c:892 [inline]
nsim_dev_trap_report_work+0x7cf/0xb80 drivers/net/netdevsim/dev.c:922
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