It's not clear why they're in use, you may want to run fuser to find out. But ultimately I guess that's a kernel bug that we can't do anything about in grub.
The real bug in grub here is bug 2029260.
It's not clear why they're in use, you may want to run fuser to find out. But ultimately I guess that's a kernel bug that we can't do anything about in grub.
The real bug in grub here is bug 2029260.