INFO: task syz.1.338:7460 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.338       state:D stack:23272 pid:7460  ppid:7158   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 perf_pending_task_sync kernel/events/core.c:5242 [inline]
 _free_event+0x174/0xf30 kernel/events/core.c:5248
 put_event kernel/events/core.c:5376 [inline]
 perf_event_release_kernel+0x836/0x8c0 kernel/events/core.c:5501
 perf_release+0x3b/0x40 kernel/events/core.c:5511
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 get_signal+0x1235/0x1400 kernel/signal.c:2678
 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9c40b8f749
RSP: 002b:00007f9c41979fe8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: fffffffffffffffc RBX: 00007f9c40de5fa0 RCX: 00007f9c40b8f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000630c1000
RBP: 00007f9c40c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f9c40de6038 R14: 00007f9c40de5fa0 R15: 00007ffc08fa5838
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/28:
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
3 locks held by kworker/u4:2/41:
 #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90000b1fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90000b1fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:286
2 locks held by kworker/1:2/967:
 #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc900043ffd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc900043ffd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
6 locks held by kworker/u4:9/2998:
 #0: ffff888017873938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017873938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc9000bf97d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc9000bf97d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8dfa8610 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x136/0xb90 net/core/net_namespace.c:606
 #3: ffff88801df96250 (&devlink->lock_key#21){+.+.}-{3:3}, at: devl_lock net/devlink/core.c:60 [inline]
 #3: ffff88801df96250 (&devlink->lock_key#21){+.+.}-{3:3}, at: devlink_pernet_pre_exit+0xe1/0x340 net/devlink/core.c:285
 #4: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: nsim_destroy+0x3f/0x180 drivers/net/netdevsim/netdev.c:417
 #5: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
 #5: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x448/0x830 kernel/rcu/tree_exp.h:1004
2 locks held by getty/5526:
 #0: ffff88814c5430a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
3 locks held by kworker/1:7/7695:
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc900035cfd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc900035cfd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffff888077e84240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x26c/0x3170 drivers/net/netdevsim/fib.c:1491

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf41/0xf80 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2998 Comm: kworker/u4:9 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net
RIP: 0010:check_prev_add kernel/locking/lockdep.c:3171 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3253 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3869 [inline]
RIP: 0010:__lock_acquire+0x47b3/0x7c80 kernel/locking/lockdep.c:5137
Code: 10 49 39 c6 0f 84 fa 04 00 00 48 89 d8 48 c1 e8 03 42 80 3c 00 00 74 12 48 89 df e8 b7 b8 75 00 49 b8 00 00 00 00 00 fc ff df <48> 8b 1b 48 8b 44 24 48 42 0f b6 04 00 84 c0 0f 85 ee 01 00 00 41
RSP: 0018:ffffc9000bf96720 EFLAGS: 00000046
RAX: 1ffffffff26d5245 RBX: ffffffff936a9228 RCX: ffffffff816746fd
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90d94508
RBP: ffffc9000bf96968 R08: dffffc0000000000 R09: 1ffffffff21b28a1
R10: dffffc0000000000 R11: fffffbfff21b28a2 R12: 0000000000000000
R13: 1ffffffff26f2605 R14: ffffffff90728df0 R15: ffff88802bf3aa18
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffffd1b3c78 CR3: 000000007d161000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 console_lock_spinning_enable kernel/printk/printk.c:1865 [inline]
 console_emit_next_record kernel/printk/printk.c:2938 [inline]
 console_flush_all+0x654/0xd00 kernel/printk/printk.c:3000
 console_unlock+0xae/0x340 kernel/printk/printk.c:3069
 vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341
 dev_vprintk_emit+0x338/0x3e0 drivers/base/core.c:4953
 dev_printk_emit+0xe1/0x130 drivers/base/core.c:4964
 __netdev_printk+0x3bf/0x4a0 net/core/dev.c:11482
 netdev_info+0x10b/0x160 net/core/dev.c:11537
 nsim_udp_tunnel_unset_port+0x2d8/0x540 drivers/net/netdevsim/udp_tunnels.c:64
 udp_tunnel_nic_device_sync_one net/ipv4/udp_tunnel_nic.c:-1 [inline]
 udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:246 [inline]
 __udp_tunnel_nic_device_sync+0xa70/0x1370 net/ipv4/udp_tunnel_nic.c:289
 udp_tunnel_nic_flush+0x4d1/0xa40 net/ipv4/udp_tunnel_nic.c:670
 udp_tunnel_nic_unregister net/ipv4/udp_tunnel_nic.c:871 [inline]
 udp_tunnel_nic_netdevice_event+0xcc2/0x12a0 net/ipv4/udp_tunnel_nic.c:911
 notifier_call_chain+0x197/0x390 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
 call_netdevice_notifiers net/core/dev.c:2078 [inline]
 unregister_netdevice_many_notify+0xf36/0x1810 net/core/dev.c:11086
 unregister_netdevice_many net/core/dev.c:11142 [inline]
 unregister_netdevice_queue+0x324/0x360 net/core/dev.c:11022
 unregister_netdevice include/linux/netdevice.h:3137 [inline]
 nsim_destroy+0x4d/0x180 drivers/net/netdevsim/netdev.c:418
 __nsim_dev_port_del+0x14d/0x1b0 drivers/net/netdevsim/dev.c:1428
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1440 [inline]
 nsim_dev_reload_destroy+0x283/0x480 drivers/net/netdevsim/dev.c:1661
 nsim_dev_reload_down+0x8a/0xc0 drivers/net/netdevsim/dev.c:968
 devlink_reload+0x137/0x600 net/devlink/dev.c:389
 devlink_pernet_pre_exit+0x18a/0x340 net/devlink/core.c:288
 ops_pre_exit_list net/core/net_namespace.c:163 [inline]
 cleanup_net+0x57f/0xb90 net/core/net_namespace.c:632
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>