Re: [REGRESSION] next/master: (build) implicit declaration of function ‘topology_core_has_smt’; did you ...

Re: [REGRESSION] next/master: (build) implicit declaration of function ‘topology_core_has_smt’; did you ...

[Randy Dunlap]

[verified still present in linux-next 20251107]
[adding CCs]


On 11/4/25 2:59 AM, KernelCI bot wrote:
> 
> 
> 
> 
> Hello,
> 
> New build issue found on next/master:
> 
> ---
>  implicit declaration of function ‘topology_core_has_smt’; did you mean ‘topology_core_cpumask’? [-Werror=implicit-function-declaration] in drivers/perf/arm_pmu.o (drivers/perf/arm_pmu.c) [logspec:kbuild,kbuild.compiler.error]
> ---
> 
> - dashboard: https://d.kernelci.org/i/maestro:b25c03bf6acc100aaa7e71de7eb2cb32868b54f5
> - giturl: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> - commit HEAD:  17490bd0527f59d841168457b245581f314b5fa0
> - tags: next-20251104
> 
> 
> Log excerpt:
> =====================================================
> drivers/perf/arm_pmu.c:935:24: error: implicit declaration of function ‘topology_core_has_smt’; did you mean ‘topology_core_cpumask’? [-Werror=implicit-function-declaration]
>   935 |         pmu->has_smt = topology_core_has_smt(cpumask_first(&pmu->supported_cpus));
>       |                        ^~~~~~~~~~~~~~~~~~~~~
>       |                        topology_core_cpumask
>   CC      drivers/iio/adc/bcm_iproc_adc.o
>   CC      drivers/devfreq/governor_simpleondemand.o
>   CC      drivers/memory/tegra/tegra124.o
>   CC      drivers/memory/brcmstb_dpfe.o
> cc1: some warnings being treated as errors
>   CC      drivers/memory/tegra/tegra20-emc.o
> 
> =====================================================
> 
> 
> # Builds where the incident occurred:
> 
> ## multi_v7_defconfig+CONFIG_SMP=n on (arm):
> - compiler: gcc-12
> - config: https://files.kernelci.org/kbuild-gcc-12-arm-SMP-6909cb01f21f07610dca0839/.config
> - dashboard: https://d.kernelci.org/build/maestro:6909cb01f21f07610dca0839
> 
> 
> #kernelci issue maestro:b25c03bf6acc100aaa7e71de7eb2cb32868b54f5
> 
> Reported-by: kernelci.org bot <bot@kernelci.org>
> 
> --
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> 

-- 
~Randy

Re: [REGRESSION] next/master: (build) implicit declaration of function ‘topology_core_has_smt’; did you ...

[Will Deacon]

On Fri, Nov 07, 2025 at 07:11:49PM -0800, Randy Dunlap wrote:
> [verified still present in linux-next 20251107]
> [adding CCs]

Should be fixed by 7ab06ea41af5 ("arch_topology: Provide a stub
topology_core_has_smt() for !CONFIG_GENERIC_ARCH_TOPOLOGY") in the Arm
perf tree (which is merged into -next).

Will