Ubuntu
initramfs-tools package

hundreds of differences in module list between initramfs-tools version 0.142ubuntu10 and version 0.142ubuntu11

Bug #2049540 reported by Dan Bungert
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
initramfs-tools (Ubuntu)
Triaged
High
Unassigned
Noble
Triaged
High
Unassigned

Bug Description

When analyzing the kernel modules present in the current initrd, I have found that there are hundreds of such differences, and that this started with the move to dracut.

I believe that the move to dracut was intended to be relatively module neutral - see LP: #2031841 and LP: #2042710 for more details on that.

I'm attaching here a test case based on podman, where different versions of the initramfs-tools package are installed, and then the list of modules present in the initrd is analyzed.

Revision history for this message
Dan Bungert (dbungert) wrote :
Revision history for this message
Dan Bungert (dbungert) wrote :
Revision history for this message
Dan Bungert (dbungert) wrote :
Revision history for this message
Dan Bungert (dbungert) wrote :
Dan Bungert (dbungert)
tags: added: rls-nn-incoming
Julian Andres Klode (juliank)
tags: added: foundations-todo
removed: rls-nn-incoming
Changed in initramfs-tools (Ubuntu):
importance: Undecided → Critical
importance: Critical → High
status: New → Triaged
Revision history for this message
Benjamin Drung (bdrung) wrote :

What is the problem here? Is there any proof that these modules are needed?

These four commit refer to bug #2031841 and cause the difference:

Filter net kernel modules by symbol regexp from dracut
https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/initramfs-tools/commit/?id=55a7cf12c037ccd14a0241aa8cab085f6f8590d8

Filter block kernel modules by symbol regex from dracut
https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/initramfs-tools/commit/?id=7ef0f4f446abe98434dcffffd2410247f95b0983

Install all usb/typec kernel modules
https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/initramfs-tools/commit/?id=aa8821f6ad59d9ce8f8cacddc5f8ae7e41178b71

Do not install ARM/RISCV specific modules on other architectures
https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/initramfs-tools/commit/?id=2df78bbb143884b9601a32608e12e43d40ccb0b0

Using symbol regexes will be more fine-grained than including whole directories.

Revision history for this message
Dan Bungert (dbungert) wrote :

Hi Ben,

> Is there any proof that these modules are needed?

It appears we have very different assumptions for how dracut was to be brought on board.

Diffstat of 0.142ubuntu1[01].log looks like:
 1 file changed, 229 insertions(+), 661 deletions(-)

That sounds like a lot of changes, in a LTS. I think we need to flip the mindset here - the status quo of the modules present should be preserved, and the differences should be justified. Do we have supporting evidence that all these changes are appropriate? The risk here is that inadequate testing happens and we get a trickle of bugs like LP: #2042710 that will need to be SRUed.

> Using symbol regexes will be more fine-grained than including whole directories.

I appreciate that the previous mechanism has certainly acquired some bloat by including whole directories, but now that is the observable shipping behavior and we risk regressing people who depend on that. How can we tell the difference?

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