Re: guide on bisecting (was Re: [REGRESSION] kexec does firmware reboot in kernel v6.7.6)

[Thorsten Leemhuis]

On 03.03.24 11:17, Pavin Joseph wrote:
> On 3/3/24 14:06, Thorsten Leemhuis wrote:
> 
>> That being said: I think I might know what sent you sideways: the main
>> section lacked a "git remote add -t master stable
>> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git";. :-((
> Now that I read through it with a fresh pair of eyes, this is exactly
> the problem!

Thx for confirming, fixed this up locally and will submit a patch to fix
this for inclusion (the text is now in -next, yeah!).

>>> 2. The "installkernel" command is called "kernel-install" in OpenSuse,
>>
>> Yeah, it looks like that, but that's not really the case. :-) In short:
>> on Fedora "installkernel" calls into kernel-install -- and
>> "installkernel" has a long history, so doing what Fedora does is likely
>> a wise thing for distros. And openSUSE had a "installkernel" as well,
>> which was part of the dracut package. Not sure if that is still the case
>> for current Leap and Tumbleweed. Could you check?
> 
> It's not available even as a symlink in OpenSuse TW / Slowroll I'm afraid.

I'm not really familiar with openSUSE, but it set up a TW container and
found that a package kernel-install-tools provides installkernel script.
Not sure how good it works though. Could you maybe test that?

>>> and it doesn't really perform all the steps to install kernel. It calls
>>> dracut to create initramfs though, but that's hardly much help.
>> Could you please elaborate a bit on that "hardly much help", as I'm not
>> really sure what you exactly mean here. Are you and/or openSUSE normally
>> not using dracut?
> I meant that calling kernel-install in OpenSuse only seems to then call
> dracut to build an initramfs for the kernel. I can call dracut myself
> without adding an unnecessary middleman (kernel-install) in the process
> and less verbosely too: dracut --kver $(make -s kernelrelease)

kernel-install is normally meant to copy the image over to /boot/ as
well afaik; maybe it did not do that in your case because you already
had placed it there manually?

> Perhaps you could add generic details such as I provided in the
> reference section for distros where installkernel doesn't exist or don't
> perform all the steps required.

Go look, they are there since the start. They differ from your
instructions though, as you put the image in /usr/lib/modules/ which
only works with distros that have kernel-install. Hmmm. Maybe it at some
point will likely be better to just use it for the manual install
instructions; but it feels a bit like it's to early for that. Not sure.

>>> 3. The dependencies for kernel building in OpenSuse and other major
>>> distros are incomplete,
>> So what was missing?
> Sorry, I don't remember.

I checked using a container and fixed this this.

> The compile/build threw some error and I looked
> up how to install kernel building dependencies in OpenSuse only to find
> out there was a pattern for it already.

I just checked, the command you provided earlier would download ~250
MByte of packages that would consume 1,5 GByte disk space, all of which
are unneeded afaics. I'm taken a bit back and forth there, but I think
sticking to just listing the packages that are actually needed might be
the better approach.

> Perhaps you could list the basic dependencies in the main section and
> provide the collection/patterns in the reference section.

I want to keep the main section distro-agnostic as much as possible;
listing package names for distros would also make it longer. I think
it's better to do that in the reference section.

>>> 4. The command to build RPM package (make binrpm-pkg) fails as the
>>> modules are installed into "/home/<user>/linux/.../lib" while depmod
>>> checks for modules in "/home/<user>/linux/.../usr/lib".
>> That sounds like a bug that should be reported and fixed, not something
>> that docs should catch and work around. Could you report that?
> Please, could you tell me where to report this bug? Kernel bugzilla?
> Which category/component?

Just sent a mail to Masahiro Yamada <masahiroy@xxxxxxxxxx> with
linux-kbuild@xxxxxxxxxxxxxxx and linux-kernel@xxxxxxxxxxxxxxx in CC.

> Thanks for all your help 😉

Thx for your feedback, it helped making things better!

Ciao, Thorsten