Bug#1106070: Fwd: linux-image-6.12.29-amd64: loop device cannot mount live squashfs any more

[Roland Clobus <rclobus@rclobus.nl>]

I forgot the @lists.debian.org, so I'll forward the bugreport.
(It is #1106070)

With kind regards,
Roland Clobus


-------- Forwarded Message --------
Subject: linux-image-6.12.29-amd64: loop device cannot mount live 
squashfs any more
Date: Mon, 19 May 2025 12:15:10 +0200
From: Roland Clobus <rclobus@rclobus.nl>
To: Debian Bug Tracking System <submit@bugs.debian.org>

Package: linux-image-6.12.29-amd64
Version: 6.12.29-1
Severity: important
X-Debbugs-Cc: debian-amd64@lists.debian.org
User: debian-amd64@lists.debian.org
Usertags: amd64
X-Debbugs-Cc: phil@hands.com
User: debian-qa@lists.debian.org
Usertags: openqa
X-Debbugs-Cc: debian-boot

Hello maintainers of the kernel,

The new kernel (6.12.29) has a modified behaviour (compared to 6.12.27) 
for the loop device.

This causes the Debian live images (for sid) to fail to boot.

The change happened between 20250518T201633Z and 20250519T021902Z, which 
matches the upload of 6.12.29 
(https://tracker.debian.org/news/1646619/accepted-linux-signed-amd64-612291-source-into-unstable/) 
at 20250518T230426Z.

To reproduce:
* Download the daily live image from 
https://openqa.debian.net/tests/396941/asset/iso/smallest-build_sid_20250519T021902Z.iso
* Boot into the live image (the first boot option)
* Result: an initramfs shell (instead of a live system) -> FAIL
* Try: `losetup -r /dev/loop1 /run/live/medium/live/filesystem.squashfs`
* Result: `failed to set up loop device: invalid argument` -> FAIL
* Try: `cp /run/live/medium/live/filesystem.squashfs /`
* Try: `losetup -r /dev/loop2 /filesystem.squashfs`
* Result: `loop2: detected capacity change from 0 to 1460312` -> PASS

It appears that the loopback device cannot be used any more with the 
mount /run/live/medium (which is on /dev/sr0).

I've verified: the md5sum of the squashfs file is OK.

The newer kernel is not in trixie yet.

With kind regards,
Roland Clobus

PS: With debian-boot in CC, since the newest kernel might be a candidate 
for trixie.

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