Re: [PATCH] perf build: prevent "argument list too long" error

[Ian Rogers]

On Tue, Mar 3, 2026 at 1:16 PM Markus Mayer <mmayer@xxxxxxxxxxxx> wrote:
>
> Due to a recent change, building perf may result in a build error when
> it is trying to "prune orphans". The file list passed to "rm" may exceed
> what the shell can handle. The build will then abort with an error like
> this:
>
>   TEST    [...]/arm64/build/linux-custom/tools/perf/pmu-events/metric_test.log
> make[5]: /bin/sh: Argument list too long
> make[5]: *** [pmu-events/Build:217: prune_orphans] Error 127
> make[5]: *** Waiting for unfinished jobs....
> make[4]: *** [Makefile.perf:773: [...]/tools/perf/pmu-events/pmu-events-in.o] Error 2
> make[4]: *** Waiting for unfinished jobs....
> make[3]: *** [Makefile.perf:289: sub-make] Error 2
>
> Processing the arguments via "xargs", instead of passing the list of
> files directly to "rm" via the shell, prevents this issue.
>
> Fixes: 36a1b0061a5 (perf build: Reduce pmu-events related copying and mkdirs)
> Signed-off-by: Markus Mayer <mmayer@xxxxxxxxxxxx>

As with:
https://lore.kernel.org/lkml/20250728093153.2330009-1-changqing.li@xxxxxxxxxxxxx/
I'm not able to reproduce the problem but the change makes sense.

Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

Thanks,
Ian

> ---
>  tools/perf/pmu-events/Build | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/pmu-events/Build b/tools/perf/pmu-events/Build
> index 63c65788d442..dc5f94862a3b 100644
> --- a/tools/perf/pmu-events/Build
> +++ b/tools/perf/pmu-events/Build
> @@ -214,7 +214,8 @@ ifneq ($(strip $(ORPHAN_FILES)),)
>  quiet_cmd_rm  = RM      $^
>
>  prune_orphans: $(ORPHAN_FILES)
> -       $(Q)$(call echo-cmd,rm)rm -f $^
> +       # The list of files can be long. Use xargs to prevent issues.
> +       $(Q)$(call echo-cmd,rm)echo "$^" | xargs rm -f
>
>  JEVENTS_DEPS += prune_orphans
>  endif
> --
> 2.52.0
>