kernel BUG in internal_create_group

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10179399b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=9c1d8f585c53781718fd
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=124a8ea5b00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1525d295b00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9c1d8f...@syzkaller.appspotmail.com

RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000003
RBP: 00007ffdf7801740 R08: 0000000000000002 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
------------[ cut here ]------------
kernel BUG at fs/sysfs/group.c:115!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 8846 Comm: syz-executor919 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:internal_create_group+0x8ef/0xb20 fs/sysfs/group.c:115 fs/sysfs/group.c:115
Code: fc ff ff e8 33 46 9d ff 48 8b 7c 24 08 e8 99 1f ff ff e9 55 fe ff ff e8 1f 46 9d ff 48 85 db 0f 85 eb f7 ff ff e8 11 46 9d ff <0f> 0b 41 bd ea ff ff ff e9 35 fe ff ff e8 ff 45 9d ff 48 83 7c 24
RSP: 0018:ffff888097f879f8 EFLAGS: 00010293
RAX: ffff88809687e240 RBX: 0000000000000000 RCX: ffffffff81c5372e
RDX: 0000000000000000 RSI: ffffffff81c53f5f RDI: 0000000000000005
RBP: ffff8880aef7c6d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8880aef7c690 R14: ffff8880aef7c6a0 R15: 0000000000000000
FS: 0000555555ceb300(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa6bb627144 CR3: 00000000b35f4000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
blk_register_queue+0x12c/0x5b0 block/blk-sysfs.c:919 block/blk-sysfs.c:919
__device_add_disk+0xe1d/0x10c0 block/genhd.c:725 block/genhd.c:725
add_disk include/linux/genhd.h:409 [inline]
add_disk include/linux/genhd.h:409 [inline] drivers/block/loop.c:2048
loop_add+0x628/0x8a0 drivers/block/loop.c:2048 drivers/block/loop.c:2048
loop_control_ioctl drivers/block/loop.c:2149 [inline]
loop_control_ioctl drivers/block/loop.c:2149 [inline] drivers/block/loop.c:2131
loop_control_ioctl+0x16c/0x480 drivers/block/loop.c:2131 drivers/block/loop.c:2131
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
vfs_ioctl fs/ioctl.c:46 [inline] fs/ioctl.c:688
file_ioctl fs/ioctl.c:501 [inline] fs/ioctl.c:688
do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688 fs/ioctl.c:688
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 fs/ioctl.c:705
__do_sys_ioctl fs/ioctl.c:712 [inline]
__se_sys_ioctl fs/ioctl.c:710 [inline]
__do_sys_ioctl fs/ioctl.c:712 [inline] fs/ioctl.c:710
__se_sys_ioctl fs/ioctl.c:710 [inline] fs/ioctl.c:710
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 fs/ioctl.c:710
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fa6bb5cf079
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdf7801728 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fa6bb5cf079
RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000003
RBP: 00007ffdf7801740 R08: 0000000000000002 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 875fa488e84fa92e ]---
RIP: 0010:internal_create_group+0x8ef/0xb20 fs/sysfs/group.c:115 fs/sysfs/group.c:115
Code: fc ff ff e8 33 46 9d ff 48 8b 7c 24 08 e8 99 1f ff ff e9 55 fe ff ff e8 1f 46 9d ff 48 85 db 0f 85 eb f7 ff ff e8 11 46 9d ff <0f> 0b 41 bd ea ff ff ff e9 35 fe ff ff e8 ff 45 9d ff 48 83 7c 24
RSP: 0018:ffff888097f879f8 EFLAGS: 00010293
RAX: ffff88809687e240 RBX: 0000000000000000 RCX: ffffffff81c5372e
RDX: 0000000000000000 RSI: ffffffff81c53f5f RDI: 0000000000000005
RBP: ffff8880aef7c6d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8880aef7c690 R14: ffff8880aef7c6a0 R15: 0000000000000000
FS: 0000555555ceb300(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa6bb627144 CR3: 00000000b35f4000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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