Re: [PATCH v4 07/10] perf tool_pmu: More accurately set the cpus for tool events

[Andres Freund]

Hi,

On 2026-02-03 15:05:39 -0800, Ian Rogers wrote:
> Thanks for the bug report! There were changes in v6.19 to change how
> metrics were computed hence the fault in the metric computation. The
> bisected patch is at fault, it aims to compute the CPU maps for tool
> events in a way to avoid unnecessary sched setaffinity calls. By
> having a smaller CPU map it set up a situation with user CPUs where
> the tool events could have no CPUs, removed from the list of events
> and the later seg fault occurred.

Thanks for the quick reply!

> I sent out a new patch series:
> https://lore.kernel.org/linux-perf-users/20260203225129.4077140-1-irogers@xxxxxxxxxx/
> that has a revert of this patch, a fix to correctly avoid the segfault in
> the prepare_metric function, and a new patch to properly reduce the CPU maps
> of the tool events. The remaining affinity reduction patches are still part
> of the series and I believe ready to land.

That sounds like it's targeted for 6.20?  I assume the revert on its own needs
to land in 6.19 (or stable if too late for 6.19) somehow?

Greetings,

Andres Freund