Bug#1058880: systemd-binfmt.service: unit fails to start when /proc/sys/fs/binfmt_misc is not mounted

[Aurelien Jarno]

Package: systemd
Version: 252.19-1~deb12u1
Severity: normal
Tags: upstream patch fixed-upstream
X-Debbugs-Cc: dsa at debian.org

Dear maintainers,

When /proc/sys/fs/binfmt_misc is not mounted (on purpose),
systemd-binfmt.service fails to start:

× systemd-binfmt.service - Set Up Additional Binary Formats
     Loaded: loaded (/lib/systemd/system/systemd-binfmt.service; static)
     Active: failed (Result: exit-code) since Sat 2023-12-16 14:27:55 UTC; 22h ago
       Docs: man:systemd-binfmt.service(8)
             man:binfmt.d(5)
             https://docs.kernel.org/admin-guide/binfmt-misc.html
             https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
   Main PID: 1408 (code=exited, status=1/FAILURE)
        CPU: 5ms

déc. 16 14:27:54 prokofiev systemd[1]: Starting systemd-binfmt.service - Set Up Additional Binary Formats...
déc. 16 14:27:54 prokofiev systemd[1]: systemd-binfmt.service: Main process exited, code=exited, status=1/FAILURE
déc. 16 14:27:54 prokofiev systemd[1]: systemd-binfmt.service: Failed with result 'exit-code'.
déc. 16 14:27:54 prokofiev systemd[1]: Failed to start systemd-binfmt.service - Set Up Additional Binary Formats.
déc. 16 14:27:55 prokofiev systemd[1]: Starting systemd-binfmt.service - Set Up Additional Binary Formats...
déc. 16 14:27:55 prokofiev systemd[1]: systemd-binfmt.service: Main process exited, code=exited, status=1/FAILURE
déc. 16 14:27:55 prokofiev systemd[1]: systemd-binfmt.service: Failed with result 'exit-code'.
déc. 16 14:27:55 prokofiev systemd[1]: Failed to start systemd-binfmt.service - Set Up Additional Binary Formats.

This has already been fixed upstream by the following commit, which is
in trixie/sid, but not in bookworm:

commit f74a7cb45c2458f90de6d37c70fa3afc1a3be279
Author: Yu Watanabe <watanabe.yu+github at gmail.com>
Date:   Sat Dec 10 11:46:45 2022 +0900

    unit: check more specific path to be written by systemd-binfmt

    Follow-up for 41807efb1594ae8e71e0255e154ea7d17be2251a.
    Replaces #25690.

Would it be possible to backport this commit to bookworm?

Thanks,
Aurelien