What were you trying to do that didn't work?

RHEL-8.10.0-20240301.1

Kernel-4.18.0-544.el8.x86_64

mdadm-4.2-13.el8.x86_64

Please provide the package NVR for which bug is seen:

Actually running:

https://gitlab.cee.redhat.com/kernel-qe/kernel/-/blob/master/storage/mdadm/20230831-new/05-raid5/0512-raid5_takeover_5_to_1.sh?ref_type=heads

Steps to reproduce

1.  Create a RAID 5 with 3  2GB loop devices first  .
   1. mdadm -CR /dev/md0 -l 5 -n 3 /dev/loop1 /dev/loop2 /dev/loop3
2. mkfs.ext4 mount to the mount point
   1. mkdir -p /mnt/md_test
   2. mkfs.ext4 /dev/md0
   3. mount /dev/md0 /mnt/md_test
3. Takeover RAID 5 to RAID 1
   1. mdadm --grow /dev/md0 --array-size 2094080
   2. mdadm --grow -n 2 /dev/md0 --backup=internal
   3. mdadm --grow /dev/md0 -l1
4. Trying to umount or stop the /dev/md0 device
   1. umount /dev/md0
   2. mdadm --stop /dev/md0

Expected results

umount successfully ,and stop the mdadm device successfully.

Actual results

When umount , it hanging there. I have to close my terminal then re-ssh to the host .checkout the mount status with lsblk , the mount point doesn't mount yet. but when I trying to mdadm --stop /dev/md0 got below error.

"""

mdadm: Cannot get exclusive access to /dev/md0:Perhaps a running process, mounted filesystem or active volume group?

"""

// code placeholder

[root@el810-202403011 20230831-new]# lsblk
NAME          MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
loop1           7:1    0    2G  0 loop  
└─md0           9:0    0    2G  0 raid1 /mnt/md_test
loop2           7:2    0    2G  0 loop  
└─md0           9:0    0    2G  0 raid1 /mnt/md_test
loop3           7:3    0    2G  0 loop  
└─md0           9:0    0    2G  0 raid1 /mnt/md_test
sda             8:0    0   50G  0 disk  
├─sda1          8:1    0  600M  0 part  /boot/efi
├─sda2          8:2    0    1G  0 part  /boot
└─sda3          8:3    0 48.4G  0 part  
  ├─rhel-root 253:0    0 46.4G  0 lvm   /
  └─rhel-swap 253:1    0  2.1G  0 lvm   [SWAP]
sr0            11:0    1 1024M  0 rom   
[root@el810-202403011 20230831-new]# umount /dev/md0 
umount: /mnt/md_test: target is busy.
[root@el810-202403011 20230831-new]# mdadm --stop /dev/md0 
mdadm: Cannot get exclusive access to /dev/md0:Perhaps a running process, mounted filesystem or active volume group?
[root@el810-202403011 20230831-new]#