Bug#1115917: reportbug: zswap compressors zstd/lz4 not availables at boot after upgrade from bookworm 12 to trixie 13

[Joaquín Alberto Calderón Pozo <kini_calderon@hotmail.com>]

Package: reportbug
Version: 13.2.0
Severity: normal
X-Debbugs-Cc: kini_calderon@hotmail.com

Dear Maintainer, in debian bookworm 12 I had zswap configured to use zstd compressor, passed by kernel parameters, after the migration/upgrade from debian bookworm 12
to trixie 13, a message log started to appear "zswap: compressor zstd not available, using default lzo". I had other machines with debian 12 yet, so I can check and test on
them, and they don't have this problem when configured zswap with zstd compressor. So... something happened between migration.

   * What led up to the situation?
	- The upgrade from bookworm 12 to trixie 13 led to dmesg "zswap: compressor zstd not available, using default lzo"
	 Before the upgrade, zswap compressors can be selected in kernel parameters at boot (/etc/default/grub) now, can't despite being configured in kernel parameters
	 and pre-load the corresponding modules in initramfs.

   * What exactly did you do (or not do) that was effective (or ineffective)?
	- Revision if files were changed after the migration: "/etc/default/grub" has "GRUB_CMDLINE_LINUX_DEFAULT=zswap.enabled=1 zswap.compressor=zstd"
	 and "/etc/initramfs-tools/modules" has "zstd".
	- Redo "update-grub" and "update-initramfs -u", ineffective.
	- Change to another compressor "lz4", modify the files acordinly "/etc/default/grub" zswap.compressor=lz4 and "/etc/initramfs-tools/modules" to have lz4
	 and redo "update-grub" and "update-initramfs -u".
	- Checking if module zstd is loaded:
		 root@kitchen:~# lsmod | grep zstd
		 zstd                   12288  4
	- Changing compressor at runtime:
		root@kitchen:~# sudo echo zstd > /sys/module/zswap/parameters/compressor
		root@kitchen:~# cat /sys/module/zswap/parameters/compressor
        	zstd

   * What was the outcome of this action?
	- zswap: compressor lz4 not available, using default lzo. Same effect as configuring zstd. Not load at boot.

   * What outcome did you expect instead?
	- The same behaviour as bookworm 12, to load the corresponding zswap compressor at boot, after the migration this is without effect to setting at boot.
	 You can instead change parameters at runtime:

	root@kitchen:~# sudo echo zstd > /sys/module/zswap/parameters/compressor
	root@kitchen:~# cat /sys/module/zswap/parameters/compressor
	zstd

Checking in internet, I am not the only one who had this problem in Debian 13 Trixie after migration, in reddit some other users has reported the same bug after the migration:

https://www.reddit.com/r/debian/comments/1n2g8fy/problems_with_zswap_on_debian_13/

And some considered to report a bug to Debian but hasn't done (acorrding to messages).

-- Package-specific info:
** Environment settings:
INTERFACE=text

** /home/kini/.reportbugrc:
reportbug_version "13.2.0"
mode standard
ui text
realname "Joaquín Alberto Calderón Pozo"
email "kini_calderon@hotmail.com"
no-cc
list-cc-me
smtphost reportbug.debian.org

-- System Information:
Debian Release: 13.1
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'proposed-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 6.12.43+deb13-amd64 (SMP w/2 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages reportbug depends on:
ii  apt                3.0.3
ii  python3            3.13.5-1
ii  python3-reportbug  13.2.0
ii  sensible-utils     0.0.25

reportbug recommends no packages.

Versions of packages reportbug suggests:
pn  claws-mail                                 <none>
ii  debconf                                    1.5.91
pn  debsums                                    <none>
pn  dlocate                                    <none>
pn  emacs-bin-common                           <none>
ii  exim4-daemon-light [mail-transport-agent]  4.98.2-1
ii  file                                       1:5.46-5
ii  gnupg                                      2.4.7-21
pn  python3-urwid                              <none>
pn  reportbug-gtk                              <none>
ii  xdg-utils                                  1.2.1-2

Versions of packages python3-reportbug depends on:
ii  apt                3.0.3
ii  file               1:5.46-5
ii  python3            3.13.5-1
ii  python3-apt        3.0.0
ii  python3-debian     1.0.1
ii  python3-debianbts  4.1.1
ii  python3-requests   2.32.3+dfsg-5
ii  sensible-utils     0.0.25

python3-reportbug suggests no packages.

-- no debconf information