Re: [PATCH] perf build-id: Fix off-by-one bug when printing kernel/module build-id

[Namhyung Kim <namhyung@kernel.org>]

On Wed, May 20, 2026 at 03:51:12PM -0300, Arnaldo Carvalho de Melo wrote:
> On Wed, May 20, 2026 at 08:55:51AM -0700, Ian Rogers wrote:
> > On Tue, May 19, 2026 at 3:39 PM Michael Petlan <mpetlan@redhat.com> wrote:
> > >
> > > When changing sprintf functions to snprintf, one byte got lost. Since
> > > snprintf ones do not handle the '\0' terminating character, the number
> > > of printed characters is 40, while sizeof(sbuild_id) is 41, including
> > > the terminating '\0' character. This makes the later check fail so that
> > > nothing is printed.
> > >
> > > Fix that.
> > >
> > > Before:
> > >     [Michael@Carbon ~]$ perf buildid-list -k
> > >     [Michael@Carbon ~]$
> > >
> > > After:
> > >     [Michael@Carbon ~]$ perf buildid-list -k
> > >     a527806324d543c4bc3ff2f9c9519d494fed5f68
> > >     [Michael@Carbon ~]$
> > >
> > > Fixes: fccaaf6fbbc5 ("perf build-id: Change sprintf functions to snprintf")
> > >
> > > Signed-off-by: Michael Petlan <mpetlan@redhat.com>
> > 
> > Tested-by: Ian Rogers <irogers@google.com>
> > also Sashiko is green for this patch:
> > https://sashiko.dev/#/patchset/20260519223855.191637-1-mpetlan%40redhat.com
> 
> Thanks, applied to perf-tools-next, for v7.2.

I sent out this a month ago, but forgot to ping for inclusion.

https://lore.kernel.org/linux-perf-users/20260420180858.129075-1-namhyung@kernel.org/

Anyway, I'm ok with fixing it either way.

Thanks,
Namhyung