BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 1e4bf6067 P4D 1e4bf6067 PUD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 366 Comm: kworker/u4:3 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: netns cleanup_net
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09d50 EFLAGS: 00010202
RAX: ffffffff8150a590 RBX: 0000000000000101 RCX: ffff8881f0dcbf00
RDX: 0000000080000101 RSI: 0000000000000000 RDI: ffff8881d483f1c0
RBP: ffff8881f6e09d90 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc13a4 R11: 1ffff1103edc13a4 R12: 00000000ffffa120
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d483f1c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001eca3a000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 call_timer_fn+0x3c/0x380 kernel/time/timer.c:1448
 expire_timers kernel/time/timer.c:1493 [inline]
 __run_timers+0x81d/0xb60 kernel/time/timer.c:1817
 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830
 __do_softirq+0x236/0x660 kernel/softirq.c:292
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1086
 </IRQ>
 do_softirq+0xf9/0x140 kernel/softirq.c:337
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:189
 local_bh_enable+0x1f/0x30 include/linux/bottom_half.h:32
 get_next_corpse net/netfilter/nf_conntrack_core.c:2069 [inline]
 nf_ct_iterate_cleanup+0x27c/0x310 net/netfilter/nf_conntrack_core.c:2092
 nf_conntrack_cleanup_net_list+0x62/0x200 net/netfilter/nf_conntrack_core.c:2279
 nf_conntrack_pernet_exit+0x146/0x160 net/netfilter/nf_conntrack_standalone.c:1153
 ops_exit_list net/core/net_namespace.c:187 [inline]
 cleanup_net+0x5fd/0xb40 net/core/net_namespace.c:612
 process_one_work+0x73b/0xcc0 kernel/workqueue.c:2290
 worker_thread+0xa5c/0x13b0 kernel/workqueue.c:2436
 kthread+0x31e/0x3a0 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354
Modules linked in:
CR2: 0000000000000000
---[ end trace 3a4ac9b26e73c1a1 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09d50 EFLAGS: 00010202
RAX: ffffffff8150a590 RBX: 0000000000000101 RCX: ffff8881f0dcbf00
RDX: 0000000080000101 RSI: 0000000000000000 RDI: ffff8881d483f1c0
RBP: ffff8881f6e09d90 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc13a4 R11: 1ffff1103edc13a4 R12: 00000000ffffa120
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d483f1c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001eca3a000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600