------------[ cut here ]------------
WARNING: CPU: 1 PID: 3558 at net/ipv4/route.c:1261 kfree_skb include/linux/skbuff.h:1234 [inline]
WARNING: CPU: 1 PID: 3558 at net/ipv4/route.c:1261 ip_rt_bug+0x28/0x120 net/ipv4/route.c:1260
Modules linked in:
CPU: 1 PID: 3558 Comm: syz-executor.1 Not tainted 6.6.0-rc1-syzkaller-00205-g4a0f07d71b04 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
RIP: 0010:ip_rt_bug+0x28/0x120 net/ipv4/route.c:1261
Code: 00 00 f3 0f 1e fa 41 54 55 53 48 89 d3 48 83 ec 08 e8 dc 3b d7 f8 66 90 e8 d5 3b d7 f8 be 02 00 00 00 48 89 df e8 48 c4 7b ff <0f> 0b 48 83 c4 08 31 c0 5b 5d 41 5c c3 e8 b6 3b d7 f8 48 8d 7b 10
RSP: 0018:ffffc900001f07c8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880859d7280 RCX: 0000000000000100
RDX: ffff888084371dc0 RSI: ffffffff88b092b8 RDI: ffffffff81ddab72
RBP: ffff8880859d7280 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff8ece2657 R11: ffffffff8a42e3b8 R12: ffff88802b19ba80
R13: ffff8880182f1380 R14: 0000000000000000 R15: ffff8880859d72d8
FS:  00007ffb2d1a76c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562c56c1f2c8 CR3: 000000008b457000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 dst_output include/net/dst.h:458 [inline]
 ip_local_out net/ipv4/ip_output.c:127 [inline]
 ip_send_skb net/ipv4/ip_output.c:1486 [inline]
 ip_push_pending_frames+0x120/0x2a0 net/ipv4/ip_output.c:1506
 icmp_push_reply+0x30f/0x450 net/ipv4/icmp.c:389
 __icmp_send+0xccc/0x17e0 net/ipv4/icmp.c:770
 ipv4_send_dest_unreach net/ipv4/route.c:1241 [inline]
 ipv4_link_failure+0x408/0xb60 net/ipv4/route.c:1248
 dst_link_failure include/net/dst.h:437 [inline]
 arp_error_report+0xcf/0x1c0 net/ipv4/arp.c:296
 neigh_invalidate+0x21c/0x560 net/core/neighbour.c:1048
 neigh_timer_handler+0xbd0/0xf50 net/core/neighbour.c:1135
 call_timer_fn+0x1a0/0x580 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x764/0xb10 kernel/time/timer.c:2022
 run_timer_softirq+0x58/0xd0 kernel/time/timer.c:2035
 __do_softirq+0x218/0x965 kernel/softirq.c:553
 invoke_softirq kernel/softirq.c:427 [inline]
 __irq_exit_rcu kernel/softirq.c:632 [inline]
 irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1074
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:batadv_hardif_get_by_netdev+0x13b/0x430 net/batman-adv/hard-interface.c:72
Code: 85 e1 02 00 00 48 8b 1b 48 81 fb e0 4e 65 92 0f 84 85 01 00 00 e8 85 83 80 f7 48 8d 7b 18 48 89 f8 48 c1 e8 03 42 80 3c 20 00 <0f> 85 ac 02 00 00 4c 39 73 18 75 b8 e8 64 83 80 f7 4c 8d 6b 20 be
RSP: 0018:ffffc9000df379d8 EFLAGS: 00000246
RAX: 1ffff11006b48203 RBX: ffff888035a41000 RCX: 0000000000000000
RDX: ffff888084371dc0 RSI: ffffffff8a074afb RDI: ffff888035a41018
RBP: ffff88808a60c000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff88808a60c000 R15: 0000000000000000
 batadv_hard_if_event+0x94/0x1660 net/batman-adv/hard-interface.c:967
 notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xb9/0x130 net/core/dev.c:1970
 call_netdevice_notifiers_extack net/core/dev.c:2008 [inline]
 call_netdevice_notifiers net/core/dev.c:2022 [inline]
 register_netdevice+0x988/0x1490 net/core/dev.c:10131
 register_netdev+0x2f/0x50 net/core/dev.c:10266
 loopback_net_init+0x7a/0x170 drivers/net/loopback.c:219
 ops_init+0xb9/0x650 net/core/net_namespace.c:136
 setup_net+0x422/0xa40 net/core/net_namespace.c:339
 copy_net_ns+0x2fa/0x670 net/core/net_namespace.c:491
 create_new_namespaces+0x3ea/0xb10 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:228
 ksys_unshare+0x3da/0x930 kernel/fork.c:3435
 __do_sys_unshare kernel/fork.c:3506 [inline]
 __se_sys_unshare kernel/fork.c:3504 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3504
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7ffb2c47cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffb2d1a70c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007ffb2c59bf80 RCX: 00007ffb2c47cae9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007ffb2c4c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007ffb2c59bf80 R15: 00007ffc8f0d0bb8
 </TASK>
----------------
Code disassembly (best guess):
   0:	85 e1                	test   %esp,%ecx
   2:	02 00                	add    (%rax),%al
   4:	00 48 8b             	add    %cl,-0x75(%rax)
   7:	1b 48 81             	sbb    -0x7f(%rax),%ecx
   a:	fb                   	sti
   b:	e0 4e                	loopne 0x5b
   d:	65 92                	gs xchg %eax,%edx
   f:	0f 84 85 01 00 00    	je     0x19a
  15:	e8 85 83 80 f7       	call   0xf780839f
  1a:	48 8d 7b 18          	lea    0x18(%rbx),%rdi
  1e:	48 89 f8             	mov    %rdi,%rax
  21:	48 c1 e8 03          	shr    $0x3,%rax
  25:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1)
* 2a:	0f 85 ac 02 00 00    	jne    0x2dc <-- trapping instruction
  30:	4c 39 73 18          	cmp    %r14,0x18(%rbx)
  34:	75 b8                	jne    0xffffffee
  36:	e8 64 83 80 f7       	call   0xf780839f
  3b:	4c 8d 6b 20          	lea    0x20(%rbx),%r13
  3f:	be                   	.byte 0xbe