Re: [PATCH] perf inject: Keep build-ID data if no option is used

[Namhyung Kim <namhyung@kernel.org>]

Hi Ian,

On Wed, Dec 17, 2025 at 10:57:01AM -0800, Ian Rogers wrote:
> On Wed, Dec 17, 2025 at 10:39 AM Namhyung Kim <namhyung@kernel.org> wrote:
> >
> > The keep_feat() determines which header features will be kept or
> > discarded.  Usually perf inject will add build-IDs based on -b, -B or
> > other related options.  But it lose build-ID when none of those options
> > are used.  This is meaningful only when --buildid-mmap is not used.
> >
> > The following example shows the impact of this change.
> >
> >   $ perf record --no-buildid-mmap true
> >   [ perf record: Woken up 1 times to write data ]
> >   [ perf record: Captured and wrote 0.037 MB perf.data (5 samples) ]
> >
> >   $ perf inject -i perf.data -o perf.data.inject
> >
> >   $ perf buildid-list -i perf.data
> >   08cccc2a9388d5247ccb3e864f3063b975b0a15d /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
> >   fd5c4d5673256cd6bda51725dba048dabb0f854e [kernel.kallsyms]
> >   97a36ce1140071be5c36b147fa0bed173e05a602 [vdso]
> >
> >   $ perf buildid-list -i perf.data.inject
> >   97a36ce1140071be5c36b147fa0bed173e05a602 [vdso]
> >
> > With this change, perf.data.inject would show the same list (of course,
> > you need to run perf inject again).
> >
> > Reported-by: Gabriel Marin <gmx@google.com>
> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> 
> Reviewed-by: Ian Rogers <irogers@google.com>

Thanks for the review!

Arnaldo, any chance you can pick this up soon?

Thanks,
Namhyung