INFO: task syz.5.4045:20193 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.4045      state:D stack:24368 pid:20193 ppid:4964   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 rwsem_down_write_slowpath+0xc99/0x1160 kernel/locking/rwsem.c:1189
 net_ns_barrier+0x11/0x20 net/core/net_namespace.c:678
 nf_ct_iterate_destroy+0x12f/0x180 net/netfilter/nf_conntrack_core.c:2527
 nfnl_cthelper_del+0x380/0x620 net/netfilter/nfnetlink_cthelper.c:721
 nfnetlink_rcv_msg+0xcab/0x1290 net/netfilter/nfnetlink.c:302
 netlink_rcv_skb+0x1ef/0x440 net/netlink/af_netlink.c:2516
 nfnetlink_rcv+0x2b0/0x2470 net/netfilter/nfnetlink.c:659
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573
 __sys_sendmsg net/socket.c:2602 [inline]
 __do_sys_sendmsg net/socket.c:2611 [inline]
 __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6659f9e159
RSP: 002b:00007f665af37028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f665a226090 RCX: 00007f6659f9e159
RDX: 0000000004048010 RSI: 00002000000001c0 RDI: 0000000000000008
RBP: 00007f665a03506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f665a226128 R14: 00007f665a226090 R15: 00007fff3d74f1c8
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2e170 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2e990 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
 #0: ffffffff8cb2d7e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2d7e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2d7e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6529
2 locks held by getty/4027:
 #0: ffff88814d83c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
2 locks held by kworker/u4:26/5842:
 #0: ffff8880b8e3acd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x98/0x130 kernel/sched/core.c:546
 #1: ffff8880b8e27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x400/0x740 kernel/sched/psi.c:999
4 locks held by kworker/u4:17/16573:
2 locks held by syz.5.4045/20193:
 #0: ffffffff97039600 (nfnl_subsys_cthelper){+.+.}-{3:3}, at: nfnl_lock net/netfilter/nfnetlink.c:98 [inline]
 #0: ffffffff97039600 (nfnl_subsys_cthelper){+.+.}-{3:3}, at: nfnetlink_rcv_msg+0xa58/0x1290 net/netfilter/nfnetlink.c:295
 #1: ffffffff8dd48210 (pernet_ops_rwsem){++++}-{3:3}, at: net_ns_barrier+0x11/0x20 net/core/net_namespace.c:678
1 lock held by syz-executor/21443:
 #0: ffffffff8dd48210 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x324/0x5b0 net/core/net_namespace.c:504

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 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+0xf0e/0xf50 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 16573 Comm: kworker/u4:17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: netns cleanup_net
RIP: 0010:check_kcov_mode kernel/kcov.c:180 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2c/0x60 kernel/kcov.c:212
Code: 04 24 65 48 8b 0d 54 3c 80 7e 65 8b 15 55 3c 80 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c <8b> 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48
RSP: 0018:ffffc90003647a80 EFLAGS: 00000246
RAX: ffffffff8877313e RBX: ffffc90003647b08 RCX: ffff88802422da00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffffff90b0f2c7 R09: 1ffffffff2161e58
R10: dffffc0000000000 R11: fffffbfff2161e59 R12: 000000000001c04d
R13: ffff88802f0e0260 R14: dffffc0000000000 R15: 1ffff920006c8f61
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0576f2d380 CR3: 000000000c88e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 get_next_corpse net/netfilter/nf_conntrack_core.c:2416 [inline]
 nf_ct_iterate_cleanup+0x4ae/0x500 net/netfilter/nf_conntrack_core.c:2470
 nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2491 [inline]
 nf_conntrack_cleanup_net_list+0xf1/0x290 net/netfilter/nf_conntrack_core.c:2604
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x78e/0xba0 net/core/net_namespace.c:640
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>