BUG: corrupted list in proto_register

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 8b2fc005 Linux 4.19.46
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14de9312a00000
kernel config: https://syzkaller.appspot.com/x/.config?x=6cad9a0b204b8583
dashboard link: https://syzkaller.appspot.com/bug?extid=25118657bd911f582fef
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+251186...@syzkaller.appspotmail.com

IPVS: ftp: loaded support on port[0] = 21
NET: Registered protocol family 30
list_add double add: new=ffffffff892e71b0, prev=ffffffff890f2d80,
next=ffffffff892e71b0.
Failed to register TIPC socket type
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:29!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8497 Comm: syz-executor.2 Not tainted 4.19.46 #18
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__list_add_valid.cold+0x26/0x3c lib/list_debug.c:29
Code: 56 ff ff ff 4c 89 e1 48 c7 c7 a0 ae 81 87 e8 00 03 31 fe 0f 0b 48 89
f2 4c 89 e1 4c 89 ee 48 c7 c7 e0 af 81 87 e8 e9 02 31 fe <0f> 0b 48 89 f1
48 c7 c7 60 af 81 87 4c 89 e6 e8 d5 02 31 fe 0f 0b
RSP: 0018:ffff888068eefb88 EFLAGS: 00010282
RAX: 0000000000000058 RBX: ffffffff892e7020 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81559e76 RDI: ffffed100d1ddf63
RBP: ffff888068eefba0 R08: 0000000000000058 R09: ffffed1015d04fe9
R10: ffffed1015d04fe8 R11: ffff8880ae827f47 R12: ffffffff892e71b0
R13: ffffffff892e71b0 R14: ffffffff892e71b0 R15: ffffffff892e7150
FS: 0000000002249940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000a75e58 CR3: 000000007e8e6000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__list_add include/linux/list.h:60 [inline]
list_add include/linux/list.h:79 [inline]
proto_register+0x459/0x8e0 net/core/sock.c:3299
tipc_socket_init+0x1c/0x70 net/tipc/socket.c:3157
tipc_init_net+0x2ed/0x570 net/tipc/core.c:69
ops_init+0xb3/0x410 net/core/net_namespace.c:129
setup_net+0x2d3/0x740 net/core/net_namespace.c:315
copy_net_ns+0x1df/0x340 net/core/net_namespace.c:438
create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107
unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206
ksys_unshare+0x440/0x980 kernel/fork.c:2525
__do_sys_unshare kernel/fork.c:2593 [inline]
__se_sys_unshare kernel/fork.c:2591 [inline]
__x64_sys_unshare+0x31/0x40 kernel/fork.c:2591
do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45bd47
Code: 00 00 00 b8 63 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 1d 8d fb ff c3
66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 10 01 00 00 0f 05 <48> 3d 01 f0 ff
ff 0f 83 fd 8c fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc9002ff28 EFLAGS: 00000202 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 000000000075c9a8 RCX: 000000000045bd47
RDX: 0000000000000000 RSI: 00007ffc9002fed0 RDI: 0000000040000000
RBP: 00000000000000f8 R08: 0000000000000000 R09: 0000000000000005
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000075c9a8
R13: 00007ffc90030198 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 6f9872a930def158 ]---
RIP: 0010:__list_add_valid.cold+0x26/0x3c lib/list_debug.c:29
Code: 56 ff ff ff 4c 89 e1 48 c7 c7 a0 ae 81 87 e8 00 03 31 fe 0f 0b 48 89
f2 4c 89 e1 4c 89 ee 48 c7 c7 e0 af 81 87 e8 e9 02 31 fe <0f> 0b 48 89 f1
48 c7 c7 60 af 81 87 4c 89 e6 e8 d5 02 31 fe 0f 0b
RSP: 0018:ffff888068eefb88 EFLAGS: 00010282
RAX: 0000000000000058 RBX: ffffffff892e7020 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81559e76 RDI: ffffed100d1ddf63
RBP: ffff888068eefba0 R08: 0000000000000058 R09: ffffed1015d04fe9
R10: ffffed1015d04fe8 R11: ffff8880ae827f47 R12: ffffffff892e71b0
R13: ffffffff892e71b0 R14: ffffffff892e71b0 R15: ffffffff892e7150
FS: 0000000002249940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000a75e58 CR3: 000000007e8e6000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

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