syzbot

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kernfs: can not remove 'nr_tags', no directory
WARNING: CPU: 0 PID: 5012 at fs/kernfs/dir.c:1656 kernfs_remove_by_name_ns+0x101/0x120 fs/kernfs/dir.c:1656
Modules linked in:
CPU: 0 PID: 5012 Comm: syz-executor164 Not tainted 6.3.0-syzkaller-13466-gfc4354c6e5c2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
RIP: 0010:kernfs_remove_by_name_ns+0x101/0x120 fs/kernfs/dir.c:1656
Code: c3 e8 d3 19 77 ff 4c 89 e7 41 bc fe ff ff ff e8 95 45 57 ff eb da e8 be 19 77 ff 4c 89 ee 48 c7 c7 a0 38 5f 8a e8 7f d6 3e ff <0f> 0b 41 bc fe ff ff ff eb bc e8 60 e8 c8 ff e9 61 ff ff ff e8 56
RSP: 0018:ffffc900033a7a38 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffffffff8d09c108 RCX: 0000000000000000
RDX: ffff88807da3c0c0 RSI: ffffffff814b2457 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: ffffffff8aa4bc00 R14: 0000000000000000 R15: 0000000000000002
FS:  00007fd887fd1700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1d209f2304 CR3: 000000001f431000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kernfs_remove_by_name include/linux/kernfs.h:618 [inline]
 remove_files+0x96/0x1c0 fs/sysfs/group.c:28
 sysfs_remove_group+0x8b/0x170 fs/sysfs/group.c:288
 sysfs_remove_groups fs/sysfs/group.c:312 [inline]
 sysfs_remove_groups+0x60/0xa0 fs/sysfs/group.c:304
 __kobject_del+0x89/0x1f0 lib/kobject.c:589
 kobject_del lib/kobject.c:621 [inline]
 kobject_del+0x40/0x60 lib/kobject.c:613
 blk_mq_unregister_hctx block/blk-mq-sysfs.c:155 [inline]
 blk_mq_unregister_hctx block/blk-mq-sysfs.c:144 [inline]
 blk_mq_sysfs_unregister_hctxs+0x24b/0x2d0 block/blk-mq-sysfs.c:283
 __blk_mq_update_nr_hw_queues block/blk-mq.c:4694 [inline]
 blk_mq_update_nr_hw_queues+0x45c/0x1020 block/blk-mq.c:4738
 nbd_start_device+0x153/0xdb0 drivers/block/nbd.c:1362
 nbd_start_device_ioctl drivers/block/nbd.c:1412 [inline]
 __nbd_ioctl drivers/block/nbd.c:1488 [inline]
 nbd_ioctl+0x21a/0xce0 drivers/block/nbd.c:1528
 blkdev_ioctl+0x372/0x7f0 block/ioctl.c:615
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fd888024309
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd887fd12e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd8880a84c0 RCX: 00007fd888024309
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007fd888075194 R08: 0000000000000002 R09: 0000000000003831
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd8880a84cc
R13: 00007fd887fd12f0 R14: 00007fd8880a84c8 R15: 0000000000000002
 </TASK>