Re: [PATCH 5.15 000/387] 5.15.197-rc2 review

[Guenter Roeck <linux@roeck-us.net>]

On 12/5/25 08:33, Greg Kroah-Hartman wrote:
> On Fri, Dec 05, 2025 at 12:59:37PM +0530, Naresh Kamboju wrote:
>> On Thu, 4 Dec 2025 at 22:14, Greg Kroah-Hartman
>> <gregkh@linuxfoundation.org> wrote:
>>>
>>> This is the start of the stable review cycle for the 5.15.197 release.
>>> There are 387 patches in this series, all will be posted as a response
>>> to this one.  If anyone has any issues with these being applied, please
>>> let me know.
>>>
>>> Responses should be made by Sat, 06 Dec 2025 16:37:24 +0000.
>>> Anything received after that time might be too late.
>>>
>>> The whole patch series can be found in one patch at:
>>>          https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.197-rc2.gz
>>> or in the git tree and branch at:
>>>          git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y
>>> and the diffstat can be found below.
>>>
>>> thanks,
>>>
>>> greg k-h
>>
>>
>> The powerpc allnoconfig failed with gcc-8 but passed with gcc-12.
>>
>> Build regression: powerpc: allnoconfig: gcc-8: Inconsistent kallsyms data
>>
>> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
>>
>> ### Build error Powerpc
>> Inconsistent kallsyms data
>> Try make KALLSYMS_EXTRA_PASS=1 as a workaround
>> make[1]: *** [Makefile:1244: vmlinux] Error 1
>>
>> ### Commit pointing to,
>>    Makefile.compiler: replace cc-ifversion with compiler-specific macros
>>    commit 88b61e3bff93f99712718db785b4aa0c1165f35c upstream.
>>
>> ### Build
>>   - https://storage.tuxsuite.com/public/linaro/lkft/builds/36OCnVeYGpKUCXtxVdz6gezHjcQ/
>>   - https://storage.tuxsuite.com/public/linaro/lkft/builds/36OCnVeYGpKUCXtxVdz6gezHjcQ/config
>>
>> ### Steps to reproduce
>>   - tuxmake --runtime podman --target-arch powerpc --toolchain gcc-8
>> --kconfig allnoconfig
> 
> Odd, this works on 5.10 ok?  What is different about 5.15 that keeps
> this from working?
> 

It is probably just a random error. I used to see this once in a while, though
not recently. Sometimes extra pass(es) are required for kallsyms to stabilize.
Some architectures are more affected than others, and it also depends on the
compiler version since different compiler versions generate different sets of
symbols. In my tests I have KALLSYMS_EXTRA_PASS=1 always enabled for alpha,
arm, and m68k. I used to have it enabled for powerpc as well, but not anymore
(if I recall correctly I stopped to see the problem there when I switched to
gcc 10).

I even submitted a patch to fix the problem several years ago, but it was
rejected.

Guenter