Subject: Re: linux-next: build failure after merge of the tip tree

From: Stephen Rothwell <[email-masked]>
Date: Mon, 17 Mar 2025 21:52:07 +1100

Hi Peter,

On Mon, 17 Mar 2025 10:38:56 +0100 Peter Zijlstra <[email-masked]> wrote:
>
> Right. Sorry for not noticing before, and thanks Jiri for poking me.
> 
> So the below resolution make it go for me. The problem appears to be
> that due to:
> 
>   bcecd5a529c1 ("percpu: repurpose __percpu tag as a named address space qualifier")
> 
> this makes that this_cpu_ptr() wants a '__percpu *', instead we feed it
> '__percpu**' which confuses things.
> 
> What would be the best way around to getting this resolved, should I
> stick the below in a fixup patch in tip/perf/core, or do we carry this
> in a merge resolution somewhere?

Its a conflict between the mm tree and the tip tree, so I will carry it
as a resolution in -next and you all should let Linus know when the
pull requests get sent.

I will use your resolution from tomorrow.

> diff --cc include/linux/perf_event.h
> index 4d0b0b007498,76f4265efee9..000000000000
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@@ -343,7 -343,7 +343,7 @@@ struct pmu 
>   	 */
>   	unsigned int			scope;
>   
> - 	struct perf_cpu_pmu_context __percpu *cpu_pmu_context;
>  -	struct perf_cpu_pmu_context __percpu **cpu_pmu_context;
> ++	struct perf_cpu_pmu_context * __percpu *cpu_pmu_context;
>   	atomic_t			exclusive_cnt; /* < 0: cpu; > 0: tsk */
>   	int				task_ctx_nr;
>   	int				hrtimer_interval_ms;

-- 
Cheers,
Stephen Rothwell