Error unmounting loop devices

[mokrunka]

Hey @krglaws , I'm getting an error when starting the build with the below errors. I'm not that familiar with loop devices actually, does this make sense to you? Seems like after this error things proceed normally, although at the end of the build there is a similar error about unmounting a loop device which causes the build to 'fail'.

[2026-02-22 17:08:54] INFO: cleaning /home/mokrunka/MyLFS-dev/lfs.img...losetup: /dev/loop1 /dev/loop2 /dev/loop0: detach failed: No such file or directory done (0.172s) [2026-02-22 17:08:54] INFO: allocating /home/mokrunka/MyLFS-dev/lfs.img... done (0.164s) [2026-02-22 17:08:54] INFO: attaching /home/mokrunka/MyLFS-dev/lfs.img to /dev/loop3... done (0.009s) [2026-02-22 17:08:54] INFO: partitioning /dev/loop3... done (0.687s) [2026-02-22 17:08:55] INFO: reattaching /dev/loop3... done (2.017s) [2026-02-22 17:08:57] INFO: exporting /dev/loop3p1's PARTUUID label... done (1.033s) [2026-02-22 17:09:00] INFO: creating image file: done (10.051s) [2026-02-22 17:09:00] INFO: mounting image... [2026-02-22 17:09:00] INFO: making sure image is unmounted... [2026-02-22 17:09:00] INFO: unmounting /home/mokrunka/MyLFS-dev/mnt/lfs... done (4.800s) [2026-02-22 17:09:05] INFO: detatching /dev/loop1 /dev/loop2 /dev/loop0 /dev/loop3...losetup: /dev/loop1 /dev/loop2 /dev/loop0 /dev/loop3: detach failed: No such file or directory failed (0.009s) [2026-02-22 17:09:05] ERROR: making sure image is unmounted: failed (4.864s) [2026-02-22 17:09:05] INFO: attaching /dev/loop4... done (0.010s) [2026-02-22 17:09:05] INFO: mounting /dev/loop4p1 onto /home/mokrunka/MyLFS-dev/mnt/lfs... done (0.109s)

[krglaws]

weird, looks like you might have your lfs.img attached to multiple loop devices. What does the output look like when you run losetup

[mokrunka]

Interesting, you're right, it is attached in multiple places:
NAME SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE DIO LOG-SEC /dev/loop1 0 0 0 0 /home/mokrunka/MyLFS-dev/lfs.img (deleted) 0 512 /dev/loop4 0 0 0 0 /home/mokrunka/MyLFS-dev/lfs.img 0 512 /dev/loop2 0 0 0 0 /home/mokrunka/MyLFS-dev/lfs.img (deleted) 0 512 /dev/loop0 0 0 1 0 /home/mokrunka/MyLFS-dev/lfs.img (deleted) 0 512 /dev/loop3 0 0 0 0 /home/mokrunka/MyLFS-dev/lfs.img 0 512
I'm not really sure why there are so many, I had to run this build a few times, starting at various pkgs in phase 4 due to some build issues I was testing on my end. Is it possible the loop devices don't get properly deleted/cleaned after a build fail/

I'm not that familiar with losetup, so I also don't know if the ones that list (deleted) would cause problems too?

[krglaws]

You will probably need to run losetup -d /dev/loop on each of those in order to clean them out. Seems like the one I have in unmount() doesn't always work for some reason. Will look into it.

[mokrunka]

Makes sense. Running losetup -D seemed to work. For the ones that were stuck in "deleted" status, a reboot got rid of them.