[CentOS] kpartx can not detach

OS: EL6 - sometimes I use

kpartx -a /mnt/.../lvdisk.img

to map the partitions and mount them via

/dev/mapper/loop0pX

After using the disk (unmounting it) I noticed that detaching such mapping via kpartx -d does not result in freeing up the loop devices. Results: System reboots shows that the filesystem where lvdisk.img is located can't be unmounted.

lsof, fuser, ps does not show any usage. Even removing the device node via

dmsetup remove /dev/mapper/loop0pX

does not help. Trying to unmount the underlying filesystem still shows /mnt: device is busy.

Any other suggestions would be greatly appreciated!

-- Thanks LF