WARNING: proc registration bug in clusterip_tg

WARNING: proc registration bug in clusterip_tg_check (2)
Status: upstream: reported on 2020/05/23 07:29
Reported-by: syzbot+35e9c587ab6de655a1b3@syzkaller.appspotmail.com
First crash: 82d, last: 21d

similar bugs (2):
Kernel	Title	Repro	Bisected	Count	Last	Reported	Patched	Status
upstream	WARNING: proc registration bug in clusterip_tg_check	C		779	900d	917d	4/17	fixed on 2018/02/26 20:04
linux-4.19	WARNING: proc registration bug in clusterip_tg_check			2	96d	138d	0/1	upstream: reported on 2020/03/27 04:23

Sample crash report:

------------[ cut here ]------------
proc_dir_entry 'ipt_CLUSTERIP/172.20.20.187' already registered
WARNING: CPU: 1 PID: 24227 at fs/proc/generic.c:371 proc_register+0x34c/0x700 fs/proc/generic.c:371
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 24227 Comm: syz-executor.5 Not tainted 5.8.0-rc6-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+0x18f/0x20d lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:231
 __warn.cold+0x20/0x45 kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:235
 exc_invalid_op+0x13/0x40 arch/x86/kernel/traps.c:255
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:540
RIP: 0010:proc_register+0x34c/0x700 fs/proc/generic.c:371
Code: df 48 89 f9 48 c1 e9 03 80 3c 01 00 0f 85 5d 03 00 00 48 8b 44 24 28 48 c7 c7 a0 d1 59 88 48 8b b0 d8 00 00 00 e8 d6 6f 60 ff <0f> 0b 48 c7 c7 c0 11 cd 89 e8 36 db 03 06 48 8b 4c 24 38 48 b8 00
RSP: 0018:ffffc9000830f620 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000040000 RSI: ffffffff815d4eb7 RDI: fffff52001061eb6
RBP: ffff88809d87fe78 R08: 0000000000000001 R09: ffff8880ae7318e7
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888086e983d8
R13: ffff8880947ab680 R14: dffffc0000000000 R15: 000000000000000d
 proc_create_data+0x130/0x190 fs/proc/generic.c:560
 clusterip_config_init net/ipv4/netfilter/ipt_CLUSTERIP.c:281 [inline]
 clusterip_tg_check+0x1741/0x1d13 net/ipv4/netfilter/ipt_CLUSTERIP.c:502
 xt_check_target+0x26c/0x650 net/netfilter/x_tables.c:1019
 check_target net/ipv4/netfilter/ip_tables.c:511 [inline]
 find_check_entry.constprop.0+0x7a9/0x9a0 net/ipv4/netfilter/ip_tables.c:553
 translate_table+0xbe1/0x1600 net/ipv4/netfilter/ip_tables.c:717
 do_replace net/ipv4/netfilter/ip_tables.c:1136 [inline]
 do_ipt_set_ctl+0x2af/0x460 net/ipv4/netfilter/ip_tables.c:1672
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x6f/0xc0 net/netfilter/nf_sockopt.c:115
 ip_setsockopt net/ipv4/ip_sockglue.c:1319 [inline]
 ip_setsockopt+0xd8/0xf0 net/ipv4/ip_sockglue.c:1299
 tcp_setsockopt+0x86/0xd0 net/ipv4/tcp.c:3334
 __sys_setsockopt+0x24a/0x480 net/socket.c:2127
 __do_sys_setsockopt net/socket.c:2143 [inline]
 __se_sys_setsockopt net/socket.c:2140 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2140
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c1f9
Code: Bad RIP value.
RSP: 002b:00007fbfd5522c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 000000000002c4c0 RCX: 000000000045c1f9
RDX: 0000000000000040 RSI: 0004000000000000 RDI: 0000000000000005
RBP: 000000000078bff0 R08: 0000000000000307 R09: 0000000000000000
R10: 0000000020001300 R11: 0000000000000246 R12: 000000000078bfac
R13: 00007ffd0f203eef R14: 00007fbfd55239c0 R15: 000000000078bfac
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (3):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Maintainers
ci-upstream-kasan-gce-selinux-root	2020/07/22 10:42	upstream	4fa640dc	128cd85f	.config	log	report	coreteam@netfilter.org, davem@davemloft.net, fw@strlen.de, kadlec@netfilter.org, kuba@kernel.org, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, pablo@netfilter.org, yoshfuji@linux-ipv6.org
ci-upstream-kasan-gce-smack-root	2020/05/22 12:22	upstream	d2f8825a	5afa2ddd	.config	log	report	coreteam@netfilter.org, davem@davemloft.net, fw@strlen.de, kadlec@netfilter.org, kuba@kernel.org, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, pablo@netfilter.org, yoshfuji@linux-ipv6.org
ci-upstream-linux-next-kasan-gce-root	2020/05/24 12:21	linux-next	c11d28ab	96c92ad3	.config	log	report	coreteam@netfilter.org, davem@davemloft.net, fw@strlen.de, kadlec@netfilter.org, kuba@kernel.org, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, pablo@netfilter.org, yoshfuji@linux-ipv6.org