xt_CT: You must specify a L4 protocol and not use inversions on it
------------[ cut here ]------------
proc_dir_entry 'ipt_hashlimit/gretap0' already registered
WARNING: CPU: 1 PID: 7455 at fs/proc/generic.c:362 proc_register+0x41e/0x590 fs/proc/generic.c:362
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 7455 Comm: syz-executor.4 Not tainted 5.6.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:221
 __warn.cold+0x2f/0x3e kernel/panic.c:582
 report_bug+0x289/0x300 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 fixup_bug arch/x86/kernel/traps.c:169 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:proc_register+0x41e/0x590 fs/proc/generic.c:362
Code: ff df 48 89 f9 48 c1 e9 03 80 3c 01 00 0f 85 5a 01 00 00 48 8b 45 d0 48 c7 c7 e0 14 59 88 48 8b b0 d0 00 00 00 e8 f1 de 5e ff <0f> 0b 48 c7 c7 20 2e cb 89 e8 34 19 0a 06 48 8b 4d a0 48 b8 00 00
RSP: 0018:ffffc90001667558 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88809d4c1bf0 RCX: 0000000000000000
RDX: 0000000000019902 RSI: ffffffff815eae46 RDI: fffff520002cce9d
RBP: ffffc900016675c0 R08: ffff88808a43e240 R09: fffffbfff16a376e
R10: fffffbfff16a376d R11: ffffffff8b51bb6f R12: ffff88808a3ae680
R13: 0000000000000000 R14: ffff88808a3ae878 R15: dffffc0000000000
 proc_create_seq_private+0x12b/0x190 fs/proc/generic.c:593
 htable_create net/netfilter/xt_hashlimit.c:341 [inline]
 hashlimit_mt_check_common.isra.0+0xb30/0x1680 net/netfilter/xt_hashlimit.c:902
 hashlimit_mt_check_v1+0x325/0x3ab net/netfilter/xt_hashlimit.c:928
 xt_check_match+0x280/0x690 net/netfilter/x_tables.c:501
 check_match net/ipv4/netfilter/ip_tables.c:472 [inline]
 find_check_match net/ipv4/netfilter/ip_tables.c:488 [inline]
 find_check_entry.isra.0+0x32f/0x920 net/ipv4/netfilter/ip_tables.c:538
 translate_table+0xcb4/0x17d0 net/ipv4/netfilter/ip_tables.c:717
 do_replace net/ipv4/netfilter/ip_tables.c:1136 [inline]
 do_ipt_set_ctl+0x2fe/0x4c2 net/ipv4/netfilter/ip_tables.c:1672
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x77/0xd0 net/netfilter/nf_sockopt.c:115
 ip_setsockopt net/ipv4/ip_sockglue.c:1260 [inline]
 ip_setsockopt+0xdf/0x100 net/ipv4/ip_sockglue.c:1240
 raw_setsockopt+0xe0/0x100 net/ipv4/raw.c:856
 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3157
 __sys_setsockopt+0x261/0x4c0 net/socket.c:2130
 __do_sys_setsockopt net/socket.c:2146 [inline]
 __se_sys_setsockopt net/socket.c:2143 [inline]
 __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2143
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c479
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f7317201c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f73172026d4 RCX: 000000000045c479
RDX: 0000000000000040 RSI: 0004000000000000 RDI: 000000000000000b
RBP: 000000000076c060 R08: 0000000000000300 R09: 0000000000000000
R10: 00000000200005c0 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a34 R14: 00000000004cc9d4 R15: 000000000076c06c
Kernel Offset: disabled
Rebooting in 86400 seconds..