general protection fault in ip6t_do_table (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    00e4db51 Merge tag 'perf-tools-2020-08-10' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1224746e900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=64a3282e09356140
dashboard link: https://syzkaller.appspot.com/bug?extid=dcaf7e1befbc40105535
compiler:       gcc (GCC) 10.1.0-syz 20200507

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+dcaf7e1befbc40105535@xxxxxxxxxxxxxxxxxxxxxxxxx

general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 21 Comm: kworker/u4:1 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
RIP: 0010:ip6t_do_table+0x289/0x1920 net/ipv6/netfilter/ip6_tables.c:286
Code: 80 3c 11 00 0f 85 f4 15 00 00 48 8b 4c 24 48 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 bd 15 00 00 48 8b 03 48 89 44 24 70 0f 1f 44 00
RSP: 0018:ffffc90000dd7650 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000008 RCX: ffff888000112800
RDX: 0000000000000001 RSI: ffff888000112840 RDI: ffff888000112838
RBP: 0000000000000001 R08: 0000000000000001 R09: ffffffff8c5eca27
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808a0b8010
R13: ffff8880499a6400 R14: ffffc90000dd78a8 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004ed650 CR3: 00000000656af000 CR4: 00000000001526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 nf_hook_entry_hookfn include/linux/netfilter.h:136 [inline]
 nf_hook_slow+0xc5/0x1e0 net/netfilter/core.c:512
 nf_hook include/linux/netfilter.h:256 [inline]
 __ip6_local_out+0x419/0x890 net/ipv6/output_core.c:167
 ip6_local_out+0x26/0x1a0 net/ipv6/output_core.c:177
 ip6tunnel_xmit include/net/ip6_tunnel.h:160 [inline]
 udp_tunnel6_xmit_skb+0x6a6/0xb90 net/ipv6/ip6_udp_tunnel.c:109
 send6+0x4cd/0xbc0 drivers/net/wireguard/socket.c:152
 wg_socket_send_skb_to_peer drivers/net/wireguard/socket.c:177 [inline]
 wg_socket_send_buffer_to_peer+0x1f9/0x340 drivers/net/wireguard/socket.c:199
 wg_packet_send_handshake_initiation+0x1fc/0x240 drivers/net/wireguard/send.c:40
 wg_packet_handshake_send_worker+0x18/0x30 drivers/net/wireguard/send.c:51
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Modules linked in:
---[ end trace c813eadb1f32ebc3 ]---
RIP: 0010:ip6t_do_table+0x289/0x1920 net/ipv6/netfilter/ip6_tables.c:286
Code: 80 3c 11 00 0f 85 f4 15 00 00 48 8b 4c 24 48 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 bd 15 00 00 48 8b 03 48 89 44 24 70 0f 1f 44 00
RSP: 0018:ffffc90000dd7650 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000008 RCX: ffff888000112800
RDX: 0000000000000001 RSI: ffff888000112840 RDI: ffff888000112838
RBP: 0000000000000001 R08: 0000000000000001 R09: ffffffff8c5eca27
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808a0b8010
R13: ffff8880499a6400 R14: ffffc90000dd78a8 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004ed650 CR3: 00000000656af000 CR4: 00000000001526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600


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