Hello all, especially Arne,
today, I upgraded to "IPFire 2.27 - Core Update 170 Development Build: next/06b4164d", which primarily comes with Linux 5.15.59 and the slab cache merging disabled. On my physical testing hardware, the boot process stalled after several kernel trace message blocks being displayed.
Unfortunately, I was unable to recover them in detail, but they occurred fairly early, roughly around the mounting of the root file system. Since the machine is semi-productive (we all test in production, don't we? ;-) ), I went back to C169 and will now investigate further which change broke the update.
An earlier version of Core Update 170 (commit 668cf4c0d0c2dbbc607716956daace413837a8da, I believe, but it was definitely after the randstruct changes) ran fine for days here, so it must be a pretty recent change. Will keep you updated.
Thanks, and best regards, Peter Müller