general protection fault in find_entry (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 9105b8aa50c1 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1430ecdd400000
kernel config: https://syzkaller.appspot.com/x/.config?x=861a3573f4e78ba1
dashboard link: https://syzkaller.appspot.com/bug?extid=0dd6360129650ab8c125
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
userspace arch: i386
CC: [adob...@gmail.com kees...@chromium.org
linux-...@vger.kernel.org linux-...@vger.kernel.org
mcg...@kernel.org]

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+0dd636...@syzkaller.appspotmail.com

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: 19046 Comm: syz-executor4 Not tainted 4.20.0-rc7+ #287
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:find_entry.isra.10+0xa4/0x1e0 fs/proc/proc_sysctl.c:119
Code: cd 00 00 00 e8 5d 21 89 ff 48 8d 7b 18 48 89 f8 48 c1 e8 03 42 80 3c
28 00 0f 85 16 01 00 00 4c 8b 7b 18 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00
0f 85 f3 00 00 00 49 8d 7f 40 4d 8b 37 48 89 f8 48
RSP: 0018:ffff888178e763c8 EFLAGS: 00010247
RAX: 0000000000000000 RBX: ffff888188c8fed8 RCX: ffffc900087fb000
RDX: 0000000000040000 RSI: ffffffff81f59683 RDI: ffff888188c8fef0
RBP: ffff888178e76408 R08: ffff8881875a44c0 R09: ffffed102f1cec84
R10: ffffed102f1cec84 R11: 0000000000000003 R12: ffff88818953d5f8
R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000006
FS: 0000000000000000(0000) GS:ffff8881daf00000(0063) knlGS:00000000f5f21b40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000020600000 CR3: 000000018c87b000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
find_subdir+0xb0/0x1a0 fs/proc/proc_sysctl.c:932
get_subdir fs/proc/proc_sysctl.c:986 [inline]
__register_sysctl_table+0x695/0xfb0 fs/proc/proc_sysctl.c:1336
register_net_sysctl+0x29/0x30 net/sysctl_net.c:120
neigh_sysctl_register+0x399/0x730 net/core/neighbour.c:3361
addrconf_sysctl_register+0xb9/0x1e0 net/ipv6/addrconf.c:6790
ipv6_add_dev+0xa86/0x13a0 net/ipv6/addrconf.c:446
addrconf_notify+0x9fb/0x2770 net/ipv6/addrconf.c:3452
notifier_call_chain+0x17e/0x380 kernel/notifier.c:93
__raw_notifier_call_chain kernel/notifier.c:394 [inline]
raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1733
call_netdevice_notifiers net/core/dev.c:1751 [inline]
register_netdevice+0xb98/0x10f0 net/core/dev.c:8570
ipip6_tunnel_create+0x49b/0x700 net/ipv6/sit.c:212
ipip6_newlink+0x155/0x360 net/ipv6/sit.c:1579
rtnl_newlink+0xf08/0x1da0 net/core/rtnetlink.c:3175
rtnetlink_rcv_msg+0x46a/0xc20 net/core/rtnetlink.c:4950
netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4968
netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
netlink_unicast+0x5a5/0x760 net/netlink/af_netlink.c:1336
netlink_sendmsg+0xa18/0xfc0 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:631
___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
__sys_sendmsg+0x11d/0x280 net/socket.c:2154
__compat_sys_sendmsg net/compat.c:754 [inline]
__do_compat_sys_sendmsg net/compat.c:761 [inline]
__se_compat_sys_sendmsg net/compat.c:758 [inline]
__ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:758
do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f88a49
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90
90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90
90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f5f210cc EFLAGS: 00000296 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace f300795086e112ea ]---
RIP: 0010:find_entry.isra.10+0xa4/0x1e0 fs/proc/proc_sysctl.c:119
Code: cd 00 00 00 e8 5d 21 89 ff 48 8d 7b 18 48 89 f8 48 c1 e8 03 42 80 3c
28 00 0f 85 16 01 00 00 4c 8b 7b 18 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00
0f 85 f3 00 00 00 49 8d 7f 40 4d 8b 37 48 89 f8 48
RSP: 0018:ffff888178e763c8 EFLAGS: 00010247
RAX: 0000000000000000 RBX: ffff888188c8fed8 RCX: ffffc900087fb000
RDX: 0000000000040000 RSI: ffffffff81f59683 RDI: ffff888188c8fef0
RBP: ffff888178e76408 R08: ffff8881875a44c0 R09: ffffed102f1cec84
R10: ffffed102f1cec84 R11: 0000000000000003 R12: ffff88818953d5f8
R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000006
FS: 0000000000000000(0000) GS:ffff8881daf00000(0063) knlGS:00000000f5f21b40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000020600000 CR3: 000000018c87b000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
kobject: 'loop5' (0000000010e1e413): kobject_uevent_env
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
syzbot.

[syzbot]

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