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

[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 <redacted>

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

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 <redacted>

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

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 <redacted>

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

On 11/10/2022 5:19 AM, Arnd Bergmann wrote:

On Thu, Nov 10, 2022, at 12:14, Naresh Kamboju wrote:

quoted

[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 <redacted>

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/