x86: clang: acpi-cpufreq.c:970:24: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]

x86: clang: acpi-cpufreq.c:970:24: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]

[Naresh Kamboju]

[Please ignore email this if it is already reported]

Kernel build warning noticed on x86_64 with clang toolchain [1].
Build failures noticed from next-20221108 .. next-20221110.

Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>

make --silent --keep-going --jobs=8
O=/home/tuxbuild/.cache/tuxmake/builds/1/build LLVM=1 LLVM_IAS=1
ARCH=x86_64 SRCARCH=x86 CROSS_COMPILE=x86_64-linux-gnu- HOSTCC=clang
CC=clang
drivers/cpufreq/acpi-cpufreq.c:970:24: error: variable 'ret' is
uninitialized when used here [-Werror,-Wuninitialized]
        acpi_cpufreq_online = ret;
                              ^~~
drivers/cpufreq/acpi-cpufreq.c:960:9: note: initialize the variable
'ret' to silence this warning
        int ret;
               ^
                = 0
1 error generated.

tuxmake --runtime podman --target-arch x86_64 --toolchain
clang-nightly --kconfig defconfig --kconfig-add
https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-kernel/linux/files/lkft.config
--kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-kernel/linux/files/lkft-crypto.config
--kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-kernel/linux/files/distro-overrides.config
--kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-kernel/linux/files/systemd.config
--kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-kernel/linux/files/virtio.config
--kconfig-add CONFIG_IGB=y --kconfig-add
CONFIG_UNWINDER_FRAME_POINTER=y LLVM=1 LLVM_IAS=1



Build log:
[1] https://builds.tuxbuild.com/2HLg3VgMgxRXBn31n6Ig7BFwSy9/


--
Linaro LKFT
https://lkft.linaro.org

Re: x86: clang: acpi-cpufreq.c:970:24: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]

[Arnd Bergmann]

On Thu, Nov 10, 2022, at 12:14, Naresh Kamboju wrote:
> [Please ignore email this if it is already reported]
>
> Kernel build warning noticed on x86_64 with clang toolchain [1].
> Build failures noticed from next-20221108 .. next-20221110.
>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
>
> make --silent --keep-going --jobs=8
> O=/home/tuxbuild/.cache/tuxmake/builds/1/build LLVM=1 LLVM_IAS=1
> ARCH=x86_64 SRCARCH=x86 CROSS_COMPILE=x86_64-linux-gnu- HOSTCC=clang
> CC=clang
> drivers/cpufreq/acpi-cpufreq.c:970:24: error: variable 'ret' is
> uninitialized when used here [-Werror,-Wuninitialized]
>         acpi_cpufreq_online = ret;
>                               ^~~
> drivers/cpufreq/acpi-cpufreq.c:960:9: note: initialize the variable
> 'ret' to silence this warning
>         int ret;
>                ^
>                 = 0
> 1 error generated.

This is caused by 13fdbc8b8da6 ("cpufreq: ACPI: Defer setting boost MSRs"),
which removes the initialization of this variable.

      Arnd

Re: x86: clang: acpi-cpufreq.c:970:24: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]

[Nathan Chancellor]

Hi Naresh,

On Thu, Nov 10, 2022 at 04:44:09PM +0530, Naresh Kamboju wrote:
> [Please ignore email this if it is already reported]
> 
> Kernel build warning noticed on x86_64 with clang toolchain [1].
> Build failures noticed from next-20221108 .. next-20221110.
> 
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> 
> make --silent --keep-going --jobs=8
> O=/home/tuxbuild/.cache/tuxmake/builds/1/build LLVM=1 LLVM_IAS=1
> ARCH=x86_64 SRCARCH=x86 CROSS_COMPILE=x86_64-linux-gnu- HOSTCC=clang
> CC=clang
> drivers/cpufreq/acpi-cpufreq.c:970:24: error: variable 'ret' is
> uninitialized when used here [-Werror,-Wuninitialized]
>         acpi_cpufreq_online = ret;
>                               ^~~
> drivers/cpufreq/acpi-cpufreq.c:960:9: note: initialize the variable
> 'ret' to silence this warning
>         int ret;
>                ^
>                 = 0
> 1 error generated.

Thanks for the report. I noticed this when it came down in next-20221108
and sent a patch for it:

https://lore.kernel.org/20221108170103.3375832-1-nathan@kernel.org/
https://github.com/ClangBuiltLinux/linux/issues/1757

It just needs to be reviewed and picked up.

Cheers,
Nathan

Re: x86: clang: acpi-cpufreq.c:970:24: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]

[stuart hayes]

On 11/10/2022 5:19 AM, Arnd Bergmann wrote:
> On Thu, Nov 10, 2022, at 12:14, Naresh Kamboju wrote:
>> [Please ignore email this if it is already reported]
>>
>> Kernel build warning noticed on x86_64 with clang toolchain [1].
>> Build failures noticed from next-20221108 .. next-20221110.
>>
>> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
>>
>> make --silent --keep-going --jobs=8
>> O=/home/tuxbuild/.cache/tuxmake/builds/1/build LLVM=1 LLVM_IAS=1
>> ARCH=x86_64 SRCARCH=x86 CROSS_COMPILE=x86_64-linux-gnu- HOSTCC=clang
>> CC=clang
>> drivers/cpufreq/acpi-cpufreq.c:970:24: error: variable 'ret' is
>> uninitialized when used here [-Werror,-Wuninitialized]
>>          acpi_cpufreq_online = ret;
>>                                ^~~
>> drivers/cpufreq/acpi-cpufreq.c:960:9: note: initialize the variable
>> 'ret' to silence this warning
>>          int ret;
>>                 ^
>>                  = 0
>> 1 error generated.
> 
> This is caused by 13fdbc8b8da6 ("cpufreq: ACPI: Defer setting boost MSRs"),
> which removes the initialization of this variable.
> 
>        Arnd

Yes, I apologize for missing that.  A patch has already been submitted to
fix this:

https://lore.kernel.org/lkml/20221108170103.3375832-1-nathan@kernel.org/