Re: Kernel Regression: Wallstreet (was Re: OldWorld ROM Macintoshes)
On 9/5/25 5:45 PM, Cedar Maxwell wrote:
On Thu, 2025-09-04 at 18:34 -0600, Stan Johnson wrote:
Cedar,
On 9/3/25 9:03 PM, Cedar Maxwell wrote:
Stan:
How did you test out all these kernels? I was trying to do so by
downloading various kernels at
https://snapshot.debian.org/binary/linux-image-powerpc/ and
installing
them with dpkg, but since they didn't generate config files in
/boot
I'm unable to create vmlinux or initrd.img files for BootX.
...
I accessed the kernels from the mainline kernel git repository.
I'm not a git expert, so I used commands adapted from a summary
provided by Finn Thain to run git bisect. If you want, I can
post the commands that I used.
Yes, please share the commands.
These are the commands that I used to run a git bisect:
On the host that you plan to use for cross-compiling:
If you have already downloaded the git repository of mainline kernels:
cd linux
git remote update
Otherwise:
git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
cd linux
You'll need to have a kernel range in mind (e.g. v5.0 was good and v5.1
was bad). And you'll need a .config file that you know is good (e.g.
dot-config-good). Then:
git clean -xdf
git reset --hard
cp ../dot-config-good .config
git checkout v5.1
git bisect start
git bisect bad
git bisect good v5.0
My build process assumes no initrd is needed.
At each build step (-jN where N is the number of processors):
make ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu- -j4 clean oldconfig
make ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu- -j4 vmlinux
Test the kernel:
I use Telnet 2.7b4 on the Wallstreet with ftp server enabled
and use ftp to transfer the kernel from the build system to
the Wallstreet. Use md5sum (or equivalent) to confirm that the
kernel transferred correctly. Boot the kernel on the Wallstreet
using BootX.
If the test is "good":
git bisect good
If the test is "bad":
git bisect bad
I you want to save the kernel, you can use something like this:
cp vmlinux ../vmlinux-`strings vmlinux | grep 'Linux version' | head
-1 | awk '{print $3}'`
Repeat for each step until the "bad commit" is identified.
...
I completed the bisect for the first failure mode and sent an email
to the author of what git identified as the "first bad commit."
Could you please CC me on any future correspondence on that chain?
ok
Reply to: