BUG: unable to handle kernel paging request in vsscanf

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: c10b57a5 Linux 4.14.176
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1671e8d7e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=457897b554d08537
dashboard link: https://syzkaller.appspot.com/bug?extid=99c845ca4c2e652efd63
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+99c845...@syzkaller.appspotmail.com

bridge175: port 1(syz_tun) entered blocking state
bridge175: port 1(syz_tun) entered disabled state
device syz_tun entered promiscuous mode
BUG: unable to handle kernel paging request at ffffffffffffffb0
IP: vsscanf+0x194/0x1fd0 lib/vsprintf.c:2760
PGD 7c6d067 P4D 7c6d067 PUD 7c6f067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 32314 Comm: syz-executor.1 Not tainted 4.14.176-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88804b0f83c0 task.stack: ffff8880432c8000
RIP: 0010:vsscanf+0x194/0x1fd0 lib/vsprintf.c:2760
RSP: 0018:ffff8880432cef98 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88803f2d52c1 RCX: ffffc90005a7c000
RDX: 0000000000000000 RSI: ffffffff863cf942 RDI: ffffffff8750bd22
RBP: ffffffffffffffb0 R08: 0000000000001000 R09: ffffed1008659e4a
R10: ffffed1008659e49 R11: ffff8880432cf24d R12: ffff88803f2d52c1
R13: ffff88803f2d52c0 R14: 0000000000000062 R15: dffffc0000000000
FS: 00007f8889464700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffb0 CR3: 0000000089f0e000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
sscanf+0xa2/0xc0 lib/vsprintf.c:3024
__dev_alloc_name+0x158/0x2b0 net/core/dev.c:1081
dev_alloc_name_ns net/core/dev.c:1144 [inline]
dev_get_valid_name+0xa0/0x1c0 net/core/dev.c:1159
register_netdevice+0x21e/0xc70 net/core/dev.c:7584
br_dev_newlink+0x23/0x100 net/bridge/br_netlink.c:1226
rtnl_newlink+0xecb/0x1720 net/core/rtnetlink.c:2728
rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4315
netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2433
netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1313
netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1878
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xc5/0x100 net/socket.c:656
___sys_sendmsg+0x70a/0x840 net/socket.c:2062
__sys_sendmsg+0xa3/0x120 net/socket.c:2096
SYSC_sendmsg net/socket.c:2107 [inline]
SyS_sendmsg+0x27/0x40 net/socket.c:2103
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c889
RSP: 002b:00007f8889463c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f88894646d4 RCX: 000000000045c889
RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000006
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009fe R14: 00000000004ccba4 R15: 000000000076bf0c
Code: 48 89 ea 48 c1 e8 03 4c 89 a4 24 a8 00 00 00 83 e2 07 45 0f b6 75 00 42 0f b6 04 38 4c 89 e3 38 d0 7f 08 84 c0 0f 85 49 17 00 00 <44> 3a 75 00 0f 84 d8 0f 00 00 e8 1d 4d 1d fb 48 b8 00 00 00 00
RIP: vsscanf+0x194/0x1fd0 lib/vsprintf.c:2760 RSP: ffff8880432cef98
CR2: ffffffffffffffb0
---[ end trace ed49066b5cdc33f8 ]---


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[syzbot]

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