general protection fault in ip6t_do_table

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b850307b Linux 4.14.184
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=125429bf100000
kernel config: https://syzkaller.appspot.com/x/.config?x=ddc0f08dd6b981c5
dashboard link: https://syzkaller.appspot.com/bug?extid=25d039c39113cb2c1fdf
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+25d039...@syzkaller.appspotmail.com

UBIFS error (pid: 32741): cannot open "(null)", error -22
kasan: CONFIG_KASAN_INLINE enabled
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
kasan: GPF could be caused by NULL-ptr deref or user memory access
Modules linked in:
CPU: 0 PID: 6304 Comm: sshd Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88808aa3a0c0 task.stack: ffff88809be58000
RIP: 0010:ip6t_do_table+0x265/0x1730 net/ipv6/netfilter/ip6_tables.c:293
RSP: 0018:ffff8880aec07888 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff888000151100
RDX: 0000000000000000 RSI: ffff888000151140 RDI: ffff888000151138
RBP: ffff8880aec07ad0 R08: 0000000000000001 R09: ffff8880aec07bc0
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880a58cfcc0
R13: ffff888050627350 R14: ffff8880a9ff9f00 R15: ffff8880aec07ba0
FS: 00007f46888598c0(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002091c000 CR3: 00000000a0d8e000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
ip6t_mangle_out net/ipv6/netfilter/ip6table_mangle.c:63 [inline]
ip6table_mangle_hook+0x2dc/0x6d0 net/ipv6/netfilter/ip6table_mangle.c:85
nf_hook_entry_hookfn include/linux/netfilter.h:108 [inline]
nf_hook_slow+0xb0/0x1a0 net/netfilter/core.c:467
nf_hook include/linux/netfilter.h:205 [inline]
NF_HOOK include/linux/netfilter.h:248 [inline]
ndisc_send_skb+0xbf1/0x1390 net/ipv6/ndisc.c:483
ndisc_send_rs+0x125/0x630 net/ipv6/ndisc.c:677
addrconf_rs_timer+0x280/0x5a0 net/ipv6/addrconf.c:3765
call_timer_fn+0x14a/0x650 kernel/time/timer.c:1279
expire_timers+0x233/0x4d0 kernel/time/timer.c:1318
__run_timers kernel/time/timer.c:1636 [inline]
run_timer_softirq+0x1d8/0x5b0 kernel/time/timer.c:1649
__do_softirq+0x254/0x9bf kernel/softirq.c:288
do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1016
</IRQ>
do_softirq kernel/softirq.c:332 [inline]
do_softirq+0xdf/0x170 kernel/softirq.c:319
__local_bh_enable_ip+0x11d/0x160 kernel/softirq.c:185
local_bh_enable include/linux/bottom_half.h:32 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:725 [inline]
ip_finish_output2+0xce7/0x1430 net/ipv4/ip_output.c:231
ip_finish_output+0x471/0xc20 net/ipv4/ip_output.c:317
NF_HOOK_COND include/linux/netfilter.h:239 [inline]
ip_output+0x1cd/0x510 net/ipv4/ip_output.c:405
dst_output include/net/dst.h:462 [inline]
ip_local_out+0x93/0x170 net/ipv4/ip_output.c:124
ip_queue_xmit+0x7ca/0x1a70 net/ipv4/ip_output.c:504
__tcp_transmit_skb+0x1831/0x2dc0 net/ipv4/tcp_output.c:1131
tcp_transmit_skb net/ipv4/tcp_output.c:1147 [inline]
tcp_write_xmit+0x56a/0x49a0 net/ipv4/tcp_output.c:2391
__tcp_push_pending_frames+0xa0/0x230 net/ipv4/tcp_output.c:2572
tcp_push+0x3fd/0x5f0 net/ipv4/tcp.c:715
tcp_sendmsg_locked+0x21f0/0x2ef0 net/ipv4/tcp.c:1426
tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1457
inet_sendmsg+0x116/0x4d0 net/ipv4/af_inet.c:762
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xb5/0x100 net/socket.c:656
sock_write_iter+0x22c/0x370 net/socket.c:925
call_write_iter include/linux/fs.h:1778 [inline]
new_sync_write fs/read_write.c:469 [inline]
__vfs_write+0x44e/0x630 fs/read_write.c:482
vfs_write+0x17f/0x4d0 fs/read_write.c:544
SYSC_write fs/read_write.c:590 [inline]
SyS_write+0xf2/0x210 fs/read_write.c:582
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f46869c2970
RSP: 002b:00007ffc68e478f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000374 RCX: 00007f46869c2970
RDX: 0000000000000374 RSI: 00005653fc942b78 RDI: 0000000000000003
RBP: 00005653fc9210a0 R08: 00007ffc68e479b0 R09: 0000000000006000
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffc68e4798f R14: 00005653fa874be7 R15: 0000000000000003
Code: 58 80 3c 11 00 0f 85 dd 12 00 00 48 8b 4c 24 30 89 c0 48 8b 51 38 48 8d 1c c2 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 a6 12 00 00 48 8b 03 48 89 44 24 68 0f 1f 44
RIP: ip6t_do_table+0x265/0x1730 net/ipv6/netfilter/ip6_tables.c:293 RSP: ffff8880aec07888
general protection fault: 0000 [#2] PREEMPT SMP KASAN
---[ end trace 1bacba5a77396039 ]---
Modules linked in:


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.