ubuntu-jammy: potential deadlock in do_deploy_deb

[MOESSBAUER, Felix]

Hi,

I have a build for ubuntu-jammy, where the do_deploy_deb sometimes
(>50% of the time) deadlocks (i.e. it never completes). I'm wondering
if this is a generic issue, which just shows up in this configuration,
or if it is really ubuntu only. On debian-bullseye and debian-bookworm
builds I cannot reproduce this.

ISAR revision: f7c0df35ae4ed44c741c98d9c003355e13e40e94

The affected package is a rebuild of the upstream evolution package.
The log of the do_deploy_deb step looks like this:

deadlock:
DEBUG: Executing shell function do_deploy_deb
Not removed as not found: evolution-plugin-spamassassin
Exporting indices...
Not removed as not found: evolution-plugins
Exporting indices...
Not removed as not found: evolution-plugin-pstimport
Exporting indices...
Not removed as not found: evolution-common
Exporting indices...
Not removed as not found: evolution
Exporting indices...

successful operation:
DEBUG: Executing shell function do_deploy_deb
Not removed as not found: evolution-plugin-spamassassin
Exporting indices...
Not removed as not found: evolution-plugins
Exporting indices...
Not removed as not found: evolution-plugin-pstimport
Exporting indices...
Not removed as not found: evolution-common
Exporting indices...
Not removed as not found: evolution
Exporting indices...
Not removed as not found: evolution-plugins-experimental
Exporting indices...
Not removed as not found: evolution-plugin-bogofilter
Exporting indices...
Not removed as not found: libevolution
Exporting indices...
Not removed as not found: evolution-dev
Exporting indices...
Exporting indices...
DEBUG: Shell function do_deploy_deb finished

Best regards,
Felix

--
Siemens AG, Technology
Linux Expert Center

[MOESSBAUER, Felix]

On Mon, 2024-06-17 at 07:48 +0000, 'MOESSBAUER, Felix' via isar-users
wrote:

> Hi,
>
> I have a build for ubuntu-jammy, where the do_deploy_deb sometimes
> (>50% of the time) deadlocks (i.e. it never completes). I'm wondering
> if this is a generic issue, which just shows up in this
> configuration,
> or if it is really ubuntu only. On debian-bullseye and debian-
> bookworm
> builds I cannot reproduce this.

After some more digging I finally found the root-cause: Ubuntu uses
zstd as compression format for the .deb packages and there is a race
condition in the tool in combination with unzstd which makes the
reprepro includedeb hang (deadlock). This is also reported in [1].

The fix is already in debian sid, but there is neither a backports, nor
a stable update available. We also cannot easily backport by ourselves
as this is a host tool which is not run in a changeroot.

This more or less renders our Ubuntu support useless, as there is no
suitable host distribution that reliably is able to build these
targets.

Anyways, I'll try to request a stable update for debian and once
merged, propose a kas container update. Long story...

Felix

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1056380