Re: [PATCH] plugins: fix -Werror=maybe-uninitialized false-positive

[Marc-André Lureau]

Hi

On Tue, Jan 14, 2025 at 8:00 PM Pierrick Bouvier
<pierrick.bouvier@linaro.org> wrote:
>
> On 1/14/25 02:48, marcandre.lureau@redhat.com wrote:
> > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> >
> > ../contrib/plugins/cache.c:638:9: error: ‘l2_cache’ may be used 
> > uninitialized [-Werror=maybe-uninitialized]
> >    638 |         append_stats_line(rep, l1_dmem_accesses, l1_dmisses,
> >        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > Is a false-positive, since cores > 1, so the variable is set in the
> > above loop.
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >   contrib/plugins/cache.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/contrib/plugins/cache.c b/contrib/plugins/cache.c
> > index 512ef6776b..c2c274cfcd 100644
> > --- a/contrib/plugins/cache.c
> > +++ b/contrib/plugins/cache.c
> > @@ -609,7 +609,7 @@ static int l2_cmp(gconstpointer a, gconstpointer b)
> >   static void log_stats(void)
> >   {
> >       int i;
> > -    Cache *icache, *dcache, *l2_cache;
> > +    Cache *icache, *dcache, *l2_cache = NULL;
> >
> >       g_autoptr(GString) rep = g_string_new("core #, data accesses, data 
> > misses,"
> >                                             " dmiss rate, insn accesses,"
>
> By the way,
>
> which compiler (version?) are you using?
> Just curious to check if we don't have any other false positives in the
> code base with it if it's a newer version.


GCC v14.2.1 from fc41.
I use '--enable-debug' '--enable-asan' '-Doptimization=g'
'-Ddebug=true' in my configure flags.
All targets do not compile with those flags.
ASAN reports various errors during make test.

Help welcome!