INFO: task kworker/u8:0:12 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:0    state:D stack:24616 pid:12    tgid:12    ppid:2      task_flags:0x4208160 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6960
 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common+0x2d7/0x4c0 kernel/sched/completion.c:100
 __wait_for_common kernel/sched/completion.c:121 [inline]
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion+0x49/0x60 kernel/sched/completion.c:153
 __flush_workqueue+0x3e2/0x1230 kernel/workqueue.c:4033
 rxrpc_destroy_all_locals+0x40/0x180 net/rxrpc/local_object.c:475
 rxrpc_exit_net+0x8b/0xc0 net/rxrpc/net_ns.c:115
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x2ee/0xab0 net/core/net_namespace.c:252
 cleanup_net+0x41b/0x830 net/core/net_namespace.c:696
 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+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:0/12:
 #0: ffff88801badf148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232
 #1: ffffc90000117c90 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233
 #2: ffffffff901042f0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x830 net/core/net_namespace.c:670
1 lock held by khungtaskd/31:
 #0: ffffffff8e3c9140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e3c9140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8e3c9140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/5595:
 #0: ffff8880313640a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
1 lock held by syz.2.608/8965:
 #0: ffffffff901042f0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x333/0x5d0 net/core/net_namespace.c:577
1 lock held by syz.0.685/9372:
 #0: ffffffff901042f0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x333/0x5d0 net/core/net_namespace.c:577
1 lock held by syz.1.728/9575:
 #0: ffffffff901042f0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x333/0x5d0 net/core/net_namespace.c:577
1 lock held by syz.3.823/10054:
 #0: ffffffff901042f0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x333/0x5d0 net/core/net_namespace.c:577
1 lock held by syz.5.832/10088:
 #0: ffffffff901042f0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x333/0x5d0 net/core/net_namespace.c:577
1 lock held by syz.4.833/10082:
 #0: ffffffff901042f0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x333/0x5d0 net/core/net_namespace.c:577
1 lock held by syz-executor/10178:
1 lock held by syz.6.952/10679:
 #0: ffff8880931f4cc8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
 #0: ffff8880931f4cc8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:652
2 locks held by rm/10745:
 #0: ffff8880b843acd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:647 [inline]
 #0: ffff8880b843acd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:632
 #1: ffff88805d198018 (&pid_list->lock){-.-.}-{2:2}, at: trace_pid_list_is_set+0x4c/0x150 kernel/trace/pid_list.c:141

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
 watchdog+0xf14/0x1140 kernel/hung_task.c:495
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 7712 Comm: kworker/u10:6 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline]
RIP: 0010:lock_acquire kernel/locking/lockdep.c:5870 [inline]
RIP: 0010:lock_acquire+0x184/0x330 kernel/locking/lockdep.c:5825
Code: 48 89 df 6a 00 6a 00 6a 00 ff b4 24 88 00 00 00 41 0f 94 c1 41 57 45 0f b6 c9 e8 17 d3 ff ff 48 c7 c7 ec fb a7 8d 48 83 c4 28 <e8> e7 93 c5 09 b8 ff ff ff ff 65 0f c1 05 92 3a 10 12 83 f8 01 0f
RSP: 0018:ffffc9000494f570 EFLAGS: 00000092
RAX: 0000000000000001 RBX: ffffffff8e3c9140 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 000000004b76aeb1 RDI: ffffffff8da7fbec
RBP: 0000000000000002 R08: 000000000c61b284 R09: 0000000090cc2b8b
R10: ffff88802b4166b0 R11: 00000000b90cc2b8 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124993000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd7a1779c8 CR3: 000000000e184000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:342 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:368
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4948 [inline]
 slab_alloc_node mm/slub.c:5258 [inline]
 kmem_cache_alloc_node_noprof+0x28a/0x7f0 mm/slub.c:5310
 __alloc_skb+0x156/0x410 net/core/skbuff.c:679
 alloc_skb include/linux/skbuff.h:1383 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:818 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:875 [inline]
 nsim_dev_trap_report_work+0x2b1/0xcf0 drivers/net/netdevsim/dev.c:921
 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+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>