Re: [PATCH 5.15 000/567] 5.15.99-rc1 review

[Linux regression tracking (Thorsten Leemhuis)]

On 08.03.23 07:24, Daniel Díaz wrote:
> 
> On 07/03/23 10:55, Greg Kroah-Hartman wrote:
>> This is the start of the stable review cycle for the 5.15.99 release.
>> There are 567 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 Thu, 09 Mar 2023 16:57:34 +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-5.15.99-rc1.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.
> 
> A new warning has been introduced on x86_64; we've seen it with GCC 8,
> 11, 12, and Clang 16.
> 
>   arch/x86/kernel/smp.o: warning: objtool: sysvec_reboot()+0x54:
> unreachable instruction
> 
> Bisection pointed towards "x86: Mark stop_this_cpu() __noreturn"
> (upstream commit f9cdf7ca57cada055f61ef6d0eb4db21c3f200db). Reverting
> this commit did remove the warning.
> 
> Reproducer:
> 
>   tuxmake \
>     --runtime podman \
>     --target-arch x86_64 \
>     --toolchain gcc-11 \
>     --kconfig
> https://storage.tuxsuite.com/public/linaro/lkft/builds/2MhGKYH63pYIllJIDAxH3FsvakK/config

FWIW, thee is another report about it here:
https://bugzilla.kernel.org/show_bug.cgi?id=217175
CCing the reporter

This is definitely not my area of expertise, so you might better want to
ignore the the following: I did some quick searching and now wonder if
backporting be0075951fde ("x86: Annotate call_on_stack()") might fix the
warning; it already was backported to 5.15 afaics:
https://lore.kernel.org/all/20220412062945.857488242@xxxxxxxxxxxxxxxxxxx/

Ciao, Thorsten