[arch-general] git bisect module against -ARCH kernel

[Bastian Beischer]

Hi,

I'm not an expert and my suggested solutions are pretty dirty, but I have
encountered this issue as well, so here are my 2 cents...

Each module stores a version string in it, which prevents it from being
loaded if it doesn't match to the one of the currently running kernel. This
string is automatically generated at compile time of the module by the
scripts provided in the linux Makefile.
If you are using git, it even includes the (short) SHA1 of the currently
checked out commit, ergo you won't be able to load modules from a bisect
just like that.

However, you can use modprobe -f, which will ignore the version string of
the module.
It's possible that this will lead to kernel crashes, though.

Another (dirty) alternative is to artificially set the version string to the
one of the currently running kernel by editing
either scripts/setlocalversion, or storing the correct string directly in
include/generated/utsrelease.h
Maybe you can also modify include/config/kernel.release

Cheers
Bastian

On Sat, Jul 23, 2011 at 4:56 PM, Matthew Monaco <dgbaley27 at 0x01b.net> wrote:

> I'm trying to bisect an issue with the microphone not working on my usb
> webcam. See the forum posting [1]. I cloned the Linus' git tree and checked
> out v2.6.39. I zcat /proc/config.gz > .config and did a make modules. I did
> this to get the symbol table and all that set up correctly.
>
> After that, I did git bisect start v2.6.39 v2.6.38 -- sound/usb
> (Everything worked fine in 2.6.38).
>
> Then for each iteration I intended to do make ${MAKEFLAGS} M=sound/usb.
> This rebuilds snd-usb-audio.ko just fine, but when I copy it to updates,
> gzip it, and run depmod, I cannot load it because modprobe says it's an
> invalid format.
>
> My only guess is that this has something to do with a version string
> somewhere, but I kept assuring it was 2.6.39 in Makefile (no extraversion).
>
> Any other ideas?
>
>
> [1] https://bbs.archlinux.org/**viewtopic.php?id=121607<https://bbs.archlinux.org/viewtopic.php?id=121607>
>



-- 
Bastian Beischer

I. Physikalisches Institut B (RWTH Aachen)
Sommerfeldstr. 14
52074 Aachen
GERMANY

Office: 28-C-203
Phone: +49 241 - 8027205