INFO: task kworker/0:4:5850 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:4     state:D stack:22616 pid:5850  ppid:2      flags:0x00004000
Workqueue: events __set_printk_clr_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5393 [inline]
 __schedule+0x156f/0x4720 kernel/sched/core.c:6722
 schedule+0xbd/0x170 kernel/sched/core.c:6796
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6855
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x689/0xce0 kernel/locking/mutex.c:747
 __ftrace_set_clr_event kernel/trace/trace_events.c:1233 [inline]
 trace_set_clr_event+0xc2/0x130 kernel/trace/trace_events.c:1299
 __set_printk_clr_event+0x22/0x80 kernel/trace/bpf_trace.c:413
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 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>

Showing all locks held in the system:
3 locks held by kworker/u4:0/11:
 #0: ffff88802defb138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #0: ffff88802defb138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #1: ffffc90000107d00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #1: ffffc90000107d00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #2: ffffffff8f3e83c8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4737
4 locks held by kworker/u4:1/12:
 #0: ffff888140049138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #0: ffff888140049138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #1: ffffc90000117d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #1: ffffc90000117d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #2: ffffffff8f3db1d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x140/0xb00 net/core/net_namespace.c:610
 #3: ffff88801ae45948 (&root->kernfs_rwsem){++++}-{3:3}, at: kernfs_remove_by_name_ns+0x7c/0x150 fs/kernfs/dir.c:1690
1 lock held by khungtaskd/29:
 #0: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6669
3 locks held by kworker/u4:2/32:
3 locks held by kworker/u4:3/50:
3 locks held by kworker/u4:8/3468:
2 locks held by getty/5540:
 #0: ffff88802fb270a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900032862f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x43a/0x1400 drivers/tty/n_tty.c:2217
3 locks held by kworker/0:4/5850:
 #0: ffff888018c70d38 ((wq_completion)events#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #0: ffff888018c70d38 ((wq_completion)events#2){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #1: ffffc90004ab7d00 (set_printk_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #1: ffffc90004ab7d00 (set_printk_work){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #2: ffffffff8e1885c8 (event_mutex){+.+.}-{3:3}, at: __ftrace_set_clr_event kernel/trace/trace_events.c:1233 [inline]
 #2: ffffffff8e1885c8 (event_mutex){+.+.}-{3:3}, at: trace_set_clr_event+0xc2/0x130 kernel/trace/trace_events.c:1299
3 locks held by kworker/1:7/12387:
8 locks held by syz.2.5710/21744:
3 locks held by kworker/u4:9/21753:
2 locks held by kworker/1:1/21772:
2 locks held by syz-executor/21789:
 #0: ffffffff8f3db1d0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x347/0x530 net/core/net_namespace.c:520
 #1: ffff88801ae45948 (&root->kernfs_rwsem){++++}-{3:3}, at: kernfs_remove_by_name_ns+0x7c/0x150 fs/kernfs/dir.c:1690
2 locks held by syz-executor/21795:
1 lock held by syz-executor/21805:
3 locks held by syz-executor/21806:
 #0: ffffffff8f3db1d0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x347/0x530 net/core/net_namespace.c:520
 #1: ffffffff8f3e83c8 (rtnl_mutex){+.+.}-{3:3}, at: ip_tunnel_init_net+0x2d2/0x7c0 net/ipv4/ip_tunnel.c:1103
 #2: ffff88801ae45948 (&root->kernfs_rwsem){++++}-{3:3}, at: kernfs_add_one+0x99/0x6b0 fs/kernfs/dir.c:778
2 locks held by syz-executor/21814:
2 locks held by sed/21821:

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

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a6/0x3e0 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+0xf59/0xfa0 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: 50 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:208
Code: 00 0f 0b 0f 1f 80 00 00 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d 0c fe 05 0e 48 89 de 5b e9 23 37 58 00 cc cc cc <f3> 0f 1e fa 48 8b 04 24 65 48 8b 0d 50 d9 7b 7e 65 8b 15 51 d9 7b
RSP: 0018:ffffc900001f05c8 EFLAGS: 00000002
RAX: 0000000000000020 RBX: 000000000000000b RCX: 0000000000000005
RDX: ffffffff8189b165 RSI: ffffffff8e17b760 RDI: 000000000000000b
RBP: 0000000000000fdc R08: ffff88801c691e00 R09: 0000000000000020
R10: 000000000000001f R11: 0000000000000100 R12: dffffc0000000000
R13: f800000000000000 R14: ffff88806b356268 R15: 00000000000451cb
FS:  0000000000000000(0000) GS:ffff8880b8d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f705aaeb6b0 CR3: 000000000df32000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 rb_event_length+0x345/0x3f0 kernel/trace/ring_buffer.c:198
 check_buffer+0x542/0x950 kernel/trace/ring_buffer.c:3493
 __rb_reserve_next+0x7ab/0xd00 kernel/trace/ring_buffer.c:3606
 rb_reserve_next_event kernel/trace/ring_buffer.c:3761 [inline]
 ring_buffer_lock_reserve+0xae1/0xed0 kernel/trace/ring_buffer.c:3820
 __trace_buffer_lock_reserve kernel/trace/trace.c:996 [inline]
 trace_event_buffer_lock_reserve+0x1d2/0x6f0 kernel/trace/trace.c:2905
 trace_event_buffer_reserve+0x2ac/0x3d0 kernel/trace/trace_events.c:661
 do_trace_event_raw_event_lock_acquire include/trace/events/lock.h:24 [inline]
 trace_event_raw_event_lock_acquire+0x128/0x290 include/trace/events/lock.h:24
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0x3ef/0x420 kernel/locking/lockdep.c:5761
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x67/0x380 lib/debugobjects.c:810
 debug_rcu_head_unqueue kernel/rcu/rcu.h:239 [inline]
 rcu_do_batch kernel/rcu/tree.c:2186 [inline]
 rcu_core+0x94a/0x17f0 kernel/rcu/tree.c:2467
 handle_softirqs+0x27d/0x820 kernel/softirq.c:578
 do_softirq+0xfa/0x1a0 kernel/softirq.c:479
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x184/0x1c0 kernel/softirq.c:406
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline]
 nsim_dev_trap_report_work+0x71b/0xa90 drivers/net/netdevsim/dev.c:851
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 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>