kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 4171 Comm: syzkaller467091 Not tainted 4.16.0-rc1+ #227
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:ipt_do_table+0x12ee/0x1950 net/ipv4/netfilter/ip_tables.c:334
RSP: 0018:ffff8801ce1769b8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8801db1a0248 RCX: ffffffff84b7913d
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801db1a00da
RBP: ffff8801ce176bc0 R08: 1ffff10039c2ed08 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff8801db1a0080 R15: ffff8801ce176b38
FS:  0000000000000000(0000) GS:ffff8801db400000(0063) knlGS:00000000089d6840
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000002000cfa0 CR3: 00000001b1021004 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 iptable_mangle_hook+0xa7/0x4a0 net/ipv4/netfilter/iptable_mangle.c:85
 nf_hook_entry_hookfn include/linux/netfilter.h:120 [inline]
 nf_hook_slow+0xba/0x1a0 net/netfilter/core.c:483
 nf_hook include/linux/netfilter.h:243 [inline]
 NF_HOOK include/linux/netfilter.h:286 [inline]
 ip_rcv+0xedf/0x1840 net/ipv4/ip_input.c:493
 __netif_receive_skb_core+0x1a41/0x3460 net/core/dev.c:4547
 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4612
 netif_receive_skb_internal+0x10b/0x670 net/core/dev.c:4686
 napi_frags_finish net/core/dev.c:5127 [inline]
 napi_gro_frags+0x58a/0xaf0 net/core/dev.c:5200
 tun_get_user+0x2760/0x3940 drivers/net/tun.c:1943
 tun_chr_write_iter+0xbd/0x1c0 drivers/net/tun.c:1988
 call_write_iter include/linux/fs.h:1781 [inline]
 do_iter_readv_writev+0x55c/0x830 fs/read_write.c:653
 do_iter_write+0x154/0x540 fs/read_write.c:932
 compat_writev+0x225/0x420 fs/read_write.c:1246
 do_compat_writev+0x115/0x220 fs/read_write.c:1267
 C_SYSC_writev fs/read_write.c:1278 [inline]
 compat_SyS_writev+0x26/0x30 fs/read_write.c:1274
 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7fc3c79
RSP: 002b:00000000ffdbee98 EFLAGS: 00000246 ORIG_RAX: 0000000000000092
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000ffdbeed4
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000004c5454 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Code: 46 52 02 75 41 e8 93 7a b9 fc 8b 85 80 fe ff ff 8d 70 01 89 b5 00 ff ff ff 48 8b b5 88 fe ff ff 4c 8d 24 c6 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 0f 85 e8 01 00 00 8b 85 00 ff ff ff 4d 89 34 24 
RIP: ipt_do_table+0x12ee/0x1950 net/ipv4/netfilter/ip_tables.c:334 RSP: ffff8801ce1769b8
---[ end trace 9cf3f7ff26001d56 ]---