[Bug]: Unable to read struct signalfd_siginfo: Bad file descriptor

[chewywater]

Checklist

• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a bug that matches the one I want to file, without success.
• If this is an issue with a particular app, I have tried filing it in the appropriate issue tracker for the app (e.g. under https://github.com/flathub/) and determined that it is an issue with Flatpak itself.
• This issue is not a report of a security vulnerability (see here if you need to report a security issue).

Flatpak version

1.12.7

What Linux distribution are you using?

Linux Mint

Linux distribution version

Linux Mint 21 Vanessa base: Ubuntu 22.04 jammy

What architecture are you using?

x86_64

How to reproduce

This issue occurs with com.borgbase.Vorta which is a GUI frontend for the backup tool borg. Borg allows mounting a backup repository using fuse. For use in the flatpak distribution of Vorta libfuse is installed as configured here and wrapped with a small script that runs fusermount through flatpak-spawn. This usually works fine but not on my machine as reported on borgbase/vorta#1424.

Borg calls backups that are stored in the same repository archives. When the vorta application runs borg mount a warning is occurs:

** (flatpak-spawn:46): WARNING **: 12:49:29.683: Unable to read struct signalfd_siginfo: Bad file descriptor

For some archives mounting works nonetheless, for others it doesn't. Since this seems to be an issue of flatpak-spawn the vorta devs redirected me to this bug tracker.
Thanks.

Expected Behavior

please see borgbase/vorta#1424

Actual Behavior

please see borgbase/vorta#1424

Additional Information

No response

[smcv]

flatpak-spawn is not actually part of flatpak, so I'm transferring the issue.

[smcv]

This actually looks like a bug in the script bundled with the Flatpak packaging of vorta, which assumes that fd 3 is a valid fd, but it isn't necessarily.

Previously seen in #55 which was caused by flathub/org.flatpak.Builder#42 and fixed by flathub/org.flatpak.Builder#47.