general protection fault in hash_ip6_uadt

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    ae608821 Merge tag 'trace-v5.5-rc5' of git://git.kernel.or..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10fe1469e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=18698c0c240ba616
dashboard link: https://syzkaller.appspot.com/bug?extid=7f87c1e8811ab0c1ca1f
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1483fec6e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10fd2325e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+7f87c1e8811ab0c1ca1f@xxxxxxxxxxxxxxxxxxxxxxxxx

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
CPU: 1 PID: 9593 Comm: syz-executor705 Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:hash_ip6_uadt+0x1f2/0x670 net/netfilter/ipset/ip_set_hash_ip.c:242
Code: 11 48 89 fa 83 e2 07 83 c2 03 38 ca 7c 08 84 c9 0f 85 c2 03 00 00 4c  
89 f2 8b 48 04 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14 02 4c  
89 f0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 80
RSP: 0018:ffffc90001dd71b0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 1ffff920003bae3a RCX: 0000000002000000
RDX: 0000000000000000 RSI: ffffffff8679051b RDI: ffff8880a24000e0
RBP: ffffc90001dd72b8 R08: 0000000000000000 R09: 0000000000000000
R10: ffffed1015d2703c R11: ffff8880ae9381e3 R12: ffffc90001dd7320
R13: ffff8880a6731200 R14: 0000000000000000 R15: ffffc90001dd7200
FS:  0000000001d64880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000058 CR3: 00000000a85bc000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ip_set_utest+0x55b/0x890 net/netfilter/ipset/ip_set_core.c:1867
 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 nfnetlink_rcv+0x1ba/0x460 net/netfilter/nfnetlink.c:563
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:659
 ____sys_sendmsg+0x753/0x880 net/socket.c:2330
 ___sys_sendmsg+0x100/0x170 net/socket.c:2384
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4403a9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffcb1400f28 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004403a9
RDX: 0000000020000000 RSI: 0000000020000180 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000401c30
R13: 0000000000401cc0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 2613125a52c78203 ]---
RIP: 0010:hash_ip6_uadt+0x1f2/0x670 net/netfilter/ipset/ip_set_hash_ip.c:242
Code: 11 48 89 fa 83 e2 07 83 c2 03 38 ca 7c 08 84 c9 0f 85 c2 03 00 00 4c  
89 f2 8b 48 04 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14 02 4c  
89 f0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 80
RSP: 0018:ffffc90001dd71b0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 1ffff920003bae3a RCX: 0000000002000000
RDX: 0000000000000000 RSI: ffffffff8679051b RDI: ffff8880a24000e0
RBP: ffffc90001dd72b8 R08: 0000000000000000 R09: 0000000000000000
R10: ffffed1015d2703c R11: ffff8880ae9381e3 R12: ffffc90001dd7320
R13: ffff8880a6731200 R14: 0000000000000000 R15: ffffc90001dd7200
FS:  0000000001d64880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000058 CR3: 00000000a85bc000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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