------------[ cut here ]------------
WARNING: CPU: 2 PID: 10979 at net/ipv4/route.c:1269 ip_rt_bug+0x2b/0x120 net/ipv4/route.c:1269
Modules linked in:
CPU: 2 UID: 0 PID: 10979 Comm: syz.0.1429 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:ip_rt_bug+0x2b/0x120 net/ipv4/route.c:1269
Code: 0f 1e fa 41 54 55 53 48 89 d3 48 83 ec 08 e8 9c 08 c3 f7 66 90 e8 95 08 c3 f7 ba 02 00 00 00 48 89 de 31 ff e8 06 69 70 ff 90 <0f> 0b 90 48 83 c4 08 31 c0 5b 5d 41 5c e9 53 2b 9f 01 e8 6e 08 c3
RSP: 0018:ffffc90005c173d8 EFLAGS: 00010283
RAX: 0000000000000c3e RBX: ffff888032e5de00 RCX: ffffc90007911000
RDX: 0000000000080000 RSI: ffffffff89f894fa RDI: ffffffff8c163400
RBP: ffff888032e5de00 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab7597 R11: 0000000000000000 R12: ffff888035e18000
R13: ffff8881013d0000 R14: ffff88805825a600 R15: ffff888032e5de58
FS:  00007fcaee5416c0(0000) GS:ffff8880d68b2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcaee540f98 CR3: 00000001123d6000 CR4: 0000000000352ef0
DR0: 0000000000000006 DR1: 0000000000000000 DR2: 0000000000000080
DR3: 000000000f000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 dst_output include/net/dst.h:461 [inline]
 dst_output include/net/dst.h:459 [inline]
 ip_local_out net/ipv4/ip_output.c:129 [inline]
 ip_send_skb net/ipv4/ip_output.c:1506 [inline]
 ip_push_pending_frames+0x419/0x5d0 net/ipv4/ip_output.c:1526
 icmp_push_reply+0x308/0x440 net/ipv4/icmp.c:394
 __icmp_send+0xcdf/0x1960 net/ipv4/icmp.c:783
 icmp_send include/net/icmp.h:43 [inline]
 ip_options_compile+0xb6/0x100 net/ipv4/ip_options.c:473
 ip_rcv_options net/ipv4/ip_input.c:287 [inline]
 ip_rcv_finish_core+0x6e1/0x22a0 net/ipv4/ip_input.c:394
 ip_rcv_finish net/ipv4/ip_input.c:452 [inline]
 NF_HOOK include/linux/netfilter.h:318 [inline]
 NF_HOOK include/linux/netfilter.h:312 [inline]
 ip_rcv+0x1c0/0x600 net/ipv4/ip_input.c:574
 __netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:5991
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6104
 netif_receive_skb_internal net/core/dev.c:6190 [inline]
 netif_receive_skb+0x137/0x7b0 net/core/dev.c:6249
 tun_rx_batched.isra.0+0x3ee/0x740 drivers/net/tun.c:1509
 tun_get_user+0x28e4/0x3ce0 drivers/net/tun.c:1950
 tun_chr_write_iter+0xdc/0x210 drivers/net/tun.c:1996
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x7d3/0x11d0 fs/read_write.c:686
 ksys_write+0x12a/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcaed78d6df
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007fcaee541000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fcaed9d5fa0 RCX: 00007fcaed78d6df
RDX: 0000000000000042 RSI: 0000200000000000 RDI: 00000000000000c8
RBP: 00007fcaed811e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000042 R11: 0000000000000293 R12: 0000000000000000
R13: 00007fcaed9d6038 R14: 00007fcaed9d5fa0 R15: 00007ffe6d74e768
 </TASK>