kernel BUG in internal_create_group

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 15a1c6b6f516 Linux 4.14.276
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14fac8e2f00000
kernel config: https://syzkaller.appspot.com/x/.config?x=3ec12c117082c76f
dashboard link: https://syzkaller.appspot.com/bug?extid=056863edfef2593853e0
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=145a10bf700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17ea09e8f00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+056863...@syzkaller.appspotmail.com

RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000003
RBP: 00007ffd000015a0 R08: 0000000000000002 R09: 00007f419d003739
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
------------[ cut here ]------------
kernel BUG at fs/sysfs/group.c:113!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 7975 Comm: syz-executor333 Not tainted 4.14.276-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88809a9e2040 task.stack: ffff88808cdc8000
RIP: 0010:internal_create_group+0x55f/0x710 fs/sysfs/group.c:113
RSP: 0018:ffff88808cdcfb00 EFLAGS: 00010297
RAX: ffff88809a9e2040 RBX: ffff8880af0db460 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880af0db460
RBP: ffff8880aaaaeef0 R08: ffffffff8b9d3418 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff88faf460
R13: ffff8880aaaaf138 R14: 0000000000000000 R15: ffff8880af0db490
FS: 00005555572cf300(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005632624ed8f0 CR3: 00000000aac56000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
blk_register_queue+0xd3/0x350 block/blk-sysfs.c:891
device_add_disk+0x97c/0xdc0 block/genhd.c:683
add_disk include/linux/genhd.h:396 [inline]
loop_add+0x615/0x830 drivers/block/loop.c:1904
loop_control_ioctl+0x11a/0x3f0 drivers/block/loop.c:2001
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f419dbe7689
RSP: 002b:00007ffd00001598 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f419dbe7689
RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000003
RBP: 00007ffd000015a0 R08: 0000000000000002 R09: 00007f419d003739
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Code: 48 c1 ea 03 80 3c 02 00 0f 84 9c fd ff ff e8 29 0c db ff e9 92 fd ff ff e8 0f 58 b1 ff 4d 85 f6 0f 85 16 fb ff ff e8 01 58 b1 ff <0f> 0b e8 fa 57 b1 ff 49 83 fe ef 74 18 e8 ef 57 b1 ff 45 89 f7
RIP: internal_create_group+0x55f/0x710 fs/sysfs/group.c:113 RSP: ffff88808cdcfb00
---[ end trace 81aab8d4d82c7505 ]---


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