Re: [PATCH v1] perf build: Add -funsigned-char to default CFLAGS

[Ian Rogers]

On Thu, Mar 26, 2026 at 3:17 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> On Fri, Mar 20, 2026 at 04:00:56PM -0700, Ian Rogers wrote:
> > On Fri, Mar 6, 2026 at 11:19 AM Ian Rogers <irogers@xxxxxxxxxx> wrote:
> > >
> > > Commit 3bc753c06dd0 ("kbuild: treat char as always unsigned") made
> > > chars unsigned by default in the Linux kernel. To avoid similar kinds
> > > of bugs and warnings, make unsigned chars the default for the perf tool.
> > >
> > > Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
>
> Do you know what the actual bug was?

I don't, my motivation was to try to avoid sashiko warnings about
issues that occur with signed chars.

Thanks,
Ian

> Thanks,
> Namhyung
>
> >
> > > ---
> > >  tools/perf/Makefile.config | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> > > index a8dc72cfe48e..3820bdf73f43 100644
> > > --- a/tools/perf/Makefile.config
> > > +++ b/tools/perf/Makefile.config
> > > @@ -349,6 +349,7 @@ CORE_CFLAGS += -fno-omit-frame-pointer
> > >  CORE_CFLAGS += -Wall
> > >  CORE_CFLAGS += -Wextra
> > >  CORE_CFLAGS += -std=gnu11
> > > +CORE_CFLAGS += -funsigned-char
> > >
> > >  CXXFLAGS += -std=gnu++17 -fno-exceptions -fno-rtti
> > >  CXXFLAGS += -Wall
> > > --
> > > 2.53.0.473.g4a7958ca14-goog
> > >