INFO: task kworker/u4:4:16037 blocked for more than 149 seconds.
      Not tainted 6.1.0-syzkaller-13872-gb6bb9676f216 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:4    state:D stack:23680 pid:16037 ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xb8a/0x5450 kernel/sched/core.c:6555
 schedule+0xde/0x1b0 kernel/sched/core.c:6631
 rxrpc_destroy_all_calls+0x1ee/0x640 net/rxrpc/call_object.c:733
 rxrpc_exit_net+0x15c/0x300 net/rxrpc/net_ns.c:125
 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169
 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:606
 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
 worker_thread+0x669/0x1090 kernel/workqueue.c:2436
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/11:
 #0: ffffffff8c78dcb0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:507
1 lock held by rcu_tasks_trace/12:
 #0: ffffffff8c78d9b0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:507
1 lock held by khungtaskd/27:
 #0: ffffffff8c78e800 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x57/0x264 kernel/locking/lockdep.c:6494
2 locks held by getty/4742:
 #0: ffff88801ce42098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x26/0x80 drivers/tty/tty_ldisc.c:244
 #1: ffffc900020382f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xef4/0x13e0 drivers/tty/n_tty.c:2177
3 locks held by kworker/u4:4/16037:
 #0: ffff888012774138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888012774138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
 #0: ffff888012774138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
 #0: ffff888012774138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
 #0: ffff888012774138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
 #0: ffff888012774138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x86d/0x1710 kernel/workqueue.c:2260
 #1: ffffc900035dfda8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8a1/0x1710 kernel/workqueue.c:2264
 #2: ffffffff8e0a0d10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9f/0xb10 net/core/net_namespace.c:568
2 locks held by syz-executor.4/1407:
 #0: ffffffff8e0a0d10 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2f8/0x6b0 net/core/net_namespace.c:479
 #1: ffffffff8c799380 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3995

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 6.1.0-syzkaller-13872-gb6bb9676f216 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x24/0x18a lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x333/0x3c0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xc75/0xfc0 kernel/hung_task.c:377
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 16062 Comm: kworker/u4:12 Not tainted 6.1.0-syzkaller-13872-gb6bb9676f216 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__this_cpu_preempt_check+0x11/0x20 lib/smp_processor_id.c:66
Code: 00 00 48 c7 c6 80 98 a6 8a 48 c7 c7 c0 98 a6 8a e9 74 fe ff ff 0f 1f 40 00 f3 0f 1e fa 55 48 89 fd 0f 1f 44 00 00 48 89 ee 5d <48> c7 c7 00 99 a6 8a e9 53 fe ff ff 0f 1f 00 f3 0f 1e fa eb 1a 0f
RSP: 0018:ffffc9000472fbb8 EFLAGS: 00000046
RAX: 0000000000000002 RBX: f2799f07f3b7e876 RCX: ffffc9000472fc10
RDX: 1ffff11008bed985 RSI: ffffffff8a4c3f00 RDI: ffffffff8a4c3f00
RBP: 1ffff920008e5f7a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000003 R14: ffff888045f6cc30 R15: ffff888045f6c200
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555556551848 CR3: 000000000c48e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lockdep_recursion_finish kernel/locking/lockdep.c:466 [inline]
 lock_release+0x3f3/0x810 kernel/locking/lockdep.c:5690
 rcu_lock_release include/linux/rcupdate.h:330 [inline]
 rcu_read_unlock include/linux/rcupdate.h:797 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0x86f/0xfa0 net/batman-adv/network-coding.c:719
 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
 worker_thread+0x669/0x1090 kernel/workqueue.c:2436
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>