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From:   Uros Bizjak <ubizjak@gmail.com>
Date:   Fri, 13 Oct 2023 11:09:40 +0200
Message-ID: <CAFULd4b7F=MNMduRn99FFcAc7Of7RsL+vyXVzsiBZZ9hz0+HnA@mail.gmail.com>
Subject: Re: [PATCH] perf/x86/amd/uncore: fix error codes in amd_uncore_init()
To:     Ingo Molnar <mingo@kernel.org>
Cc:     Dan Carpenter <dan.carpenter@linaro.org>,
        Sandipan Das <sandipan.das@amd.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, linux-perf-users@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
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On Fri, Oct 13, 2023 at 11:06=E2=80=AFAM Ingo Molnar <mingo@kernel.org> wro=
te:
>
>
> * Dan Carpenter <dan.carpenter@linaro.org> wrote:
>
> > On Fri, Oct 13, 2023 at 09:30:46AM +0200, Ingo Molnar wrote:
> >
> > > Ugh, why on Earth didn't GCC warn about this? The bad pattern is pret=
ty
> > > simple & obvious once pointed out ... compilers should have no troubl=
e
> > > realizing that 'ret' is returned uninitialized in some of these contr=
ol
> > > paths. Yet not a peep from the compiler ...
> >
> > We disabled that warning years ago (5?) because GCC had too many false
> > positives.
>
> GCC had some pretty bogus notions about 'possible' uninitialized use that
> encouraged some bad code patterns, but in this case there's readily
> provable uninitialized use, that a compiler should warn about.
>
> Is it possible to disable just the unreliable, probabilistic part of GCC'=
s
> uninitialized variables warnings?

-Wno-maybe-uninitialized?

Uros.