could not attach image file to loop device: no loop devices available about singularity

[alfaro96]

@alfaro96 - thanks for this information. That environment will likely be a bit easier for us to replicate than the exact arch Linux one.

I'll be able to take a deeper look into this tomorrow.

Thank you @dtrudg for the quick response!

I have granted access to the loop devices and the problem has been solved. That is why I deleted the original comment, to avoid disturbance in this issue.

[dtrudg]

If you have an issue with loop device creation, that is not solved by updating to the current version of SingularityCE, then please open a new issue for it - providing as much information as you can. It is likely to have a different cause than old issues reported with older versions of Singularity and the kernel.

[dtrudg]

Thanks for the information there - it's not yet clear exactly what is going on.

When you say it used to work, but now doesn't - did 3.7.3 work previously, or was it an older version that works?

Has your kernel recently been upgraded? Could you give output of uname -a just in case that's related? Also check in dmesg output for any errors that might look relevant. Thanks.

[dtrudg]

@alfaro96 - thanks for this information. That environment will likely be a bit easier for us to replicate than the exact arch Linux one.

I'll be able to take a deeper look into this tomorrow.

[a-ludi]

Sadly, I do not know exactly which version worked for me and I cannot try it out because the release tarballs on GitHub are not available anymore - it likely was v3.5.2.

Yes, my kernel has been updated. It is continuously being updated, that's part of Arch linux.

There are no message in dmesg when I try to run the container.

Here is the system info:

$ uname -a
Linux *** 5.12.3-arch1-1 #1 SMP PREEMPT Wed, 12 May 2021 17:54:18 +0000 x86_64 GNU/Linux

[dtrudg]

Hi @a-ludi - I haven't been able to replicate yet, in a simple arch VM I have. This is going to need a bit more effort when I have an afternoon, as we don't routinely test on Arch Linux, and I cannot reproduce under Fedora which I regularly use and is tracking new kernels.

Sadly, I do not know exactly which version worked for me and I cannot try it out because the release tarballs on GitHub are not available anymore - it likely was v3.5.2.

Please see: #68

The older releases can be found at github.com/hpcng/singularity/releases

This location is a fork from SingularityCE 3.8.0 onward. Unfortunately it was previously a redirect to the hpcng/singularity address and many were not aware of the prior move to that hpcng/singularity location.

[a-ludi]

Quick update: 3.5.2 works. (Thanks for the pointer to hpcng for some reason I did not find it there earlier.)

I will try to determine the latest working version and report back.

[a-ludi]

Weirdly, after trying different version, 3.7.3 now works just fine - the error is gone. Maybe the error arose because build files from older release were kept and reused for the 3.7.3 build. Thanks for your support anyway!

[dtrudg]

Thanks for updating us!

[richelbilderbeek]

@alfaro96 I have exactly the same problem and you seem to have found a solution. I quote:

I have granted access to the loop devices and the problem has been solved.

How did you do this?

Would be great to find en even better solution here :-)

[hiiiyilingzhang]

I've encountered the issue after reboot server. It worked totally fine for v3.10.2 before reboot, but it shows the following errors now:

FATAL:   container creation failed: mount /proc/self/fd/3->/usr/local/var/singularity/mnt/session/rootfs error: while mounting image /proc/self/fd/3: failed to find loop device: could not attach image file to loop device: no loop devices available

Then I update to v3.11.4 since I notice v3.11.2 patch release fix the bug by using /dev/loop-control for loop device creation. But it issue still exits.

Same with the issue author, there are enough loop devices available:

$ ls /dev/loop*
/dev/loop0    /dev/loop121  /dev/loop145  /dev/loop169  /dev/loop192  /dev/loop255  (and more...)
$ mount | grep loop
(empty output)

Here's system info:

uname -a
Linux xxx-ubuntu 5.15.0-78-generic #85~20.04.1-Ubuntu SMP Mon Jul 17 09:42:39 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

Looking forward to your replies.