general protection fault in __xfrm6_tunnel_spi_lookup

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    be978f8f Add linux-next specific files for 20200713
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=156005af100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3fe4fccb94cbc1a6
dashboard link: https://syzkaller.appspot.com/bug?extid=27016009dfe6ab82bff1
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=150269c0900000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=164e1d77100000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+27016009dfe6ab82bff1@xxxxxxxxxxxxxxxxxxxxxxxxx

general protection fault, probably for non-canonical address 0xdffffc0000000104: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000820-0x0000000000000827]
CPU: 0 PID: 6792 Comm: syz-executor232 Not tainted 5.8.0-rc4-next-20200713-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:ipv6_addr_equal include/net/ipv6.h:579 [inline]
RIP: 0010:xfrm6_addr_equal include/net/xfrm.h:1699 [inline]
RIP: 0010:__xfrm6_tunnel_spi_lookup+0x22b/0x3b0 net/ipv6/xfrm6_tunnel.c:82
Code: 89 e0 48 c1 e8 03 80 3c 28 00 0f 85 5b 01 00 00 4d 8b 24 24 4d 85 e4 74 53 e8 31 fa 7b fa 49 8d 7c 24 20 48 89 f8 48 c1 e8 03 <80> 3c 28 00 0f 85 2d 01 00 00 4d 8b 7c 24 20 49 8d 7c 24 28 48 89
RSP: 0018:ffffc90001277580 EFLAGS: 00010202
RAX: 0000000000000104 RBX: ffffffffffffffff RCX: ffffffff86f83788
RDX: ffff8880947443c0 RSI: ffffffff86f8373f RDI: 0000000000000820
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffff888094744c90
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000800
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  000000000162d880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000180 CR3: 0000000098519000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 xfrm6_tunnel_spi_lookup+0x8a/0x1d0 net/ipv6/xfrm6_tunnel.c:95
 ipcomp6_tunnel_attach net/ipv6/ipcomp6.c:119 [inline]
 ipcomp6_init_state net/ipv6/ipcomp6.c:159 [inline]
 ipcomp6_init_state+0x1de/0x700 net/ipv6/ipcomp6.c:139
 __xfrm_init_state+0x9a6/0x14b0 net/xfrm/xfrm_state.c:2498
 xfrm_init_state+0x1a/0x70 net/xfrm/xfrm_state.c:2525
 pfkey_msg2xfrm_state net/key/af_key.c:1291 [inline]
 pfkey_add+0x1a10/0x2b70 net/key/af_key.c:1508
 pfkey_process+0x66d/0x7a0 net/key/af_key.c:2834
 pfkey_sendmsg+0x42d/0x800 net/key/af_key.c:3673
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x331/0x810 net/socket.c:2363
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2417
 __sys_sendmmsg+0x195/0x480 net/socket.c:2507
 __do_sys_sendmmsg net/socket.c:2536 [inline]
 __se_sys_sendmmsg net/socket.c:2533 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2533
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4403d9
Code: Bad RIP value.
RSP: 002b:00007ffeb96d2058 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004403d9
RDX: 0000000000000393 RSI: 0000000020000180 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401be0
R13: 0000000000401c70 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 224ae9c97b2f647b ]---
RIP: 0010:ipv6_addr_equal include/net/ipv6.h:579 [inline]
RIP: 0010:xfrm6_addr_equal include/net/xfrm.h:1699 [inline]
RIP: 0010:__xfrm6_tunnel_spi_lookup+0x22b/0x3b0 net/ipv6/xfrm6_tunnel.c:82
Code: 89 e0 48 c1 e8 03 80 3c 28 00 0f 85 5b 01 00 00 4d 8b 24 24 4d 85 e4 74 53 e8 31 fa 7b fa 49 8d 7c 24 20 48 89 f8 48 c1 e8 03 <80> 3c 28 00 0f 85 2d 01 00 00 4d 8b 7c 24 20 49 8d 7c 24 28 48 89
RSP: 0018:ffffc90001277580 EFLAGS: 00010202
RAX: 0000000000000104 RBX: ffffffffffffffff RCX: ffffffff86f83788
RDX: ffff8880947443c0 RSI: ffffffff86f8373f RDI: 0000000000000820
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffff888094744c90
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000800
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  000000000162d880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000180 CR3: 0000000098519000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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