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From:   Anders Roxell <anders.roxell@linaro.org>
Date:   Tue, 13 Jul 2021 17:32:17 +0200
Message-ID: <CADYN=9+vr=xHsY8yinyWUTN+xyEG=v8-xf4y2psDarFKWDU6xA@mail.gmail.com>
Subject: Re: perf: bench/sched-messaging.c:73:13: error: 'dummy' may be used uninitialized
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Naresh Kamboju <naresh.kamboju@linaro.org>,
        perf-users <perf-users@linaro.org>,
        open list <linux-kernel@vger.kernel.org>,
        linux-stable <stable@vger.kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Sasha Levin <sashal@kernel.org>, Leo Yan <leo.yan@linaro.org>
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On Tue, 13 Jul 2021 at 17:18, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Tue, Jul 13, 2021 at 08:40:28PM +0530, Naresh Kamboju wrote:
> > LKFT have noticed these warnings / errors when we have updated gcc version from
> > gcc-9 to gcc-11 on stable-rc linux-5.4.y branch. I have provided the steps to
> > reproduce in this email below.
> >
> > Following perf builds failed with gcc-11 with linux-5.4.y branch.
> > - build-arm-gcc-11-perf
> > - build-arm64-gcc-11-perf
> > - build-i386-gcc-11-perf
> > - build-x86-gcc-11-perf
> >
> > Build error log:
> > --------------------
>
> <snip>
>
> I imagine this is fixed in newer kernel versions, so if you could
> provide the git ids of the patches needed to fix this up in 5.4, that
> would be great!

You were correct, I did a bisect [1] and found
d493720581a6 ("perf bench: Fix 2 memory sanitizer warnings").

commit d2c73501a767514b6c85c7feff9457a165d51057 upstream.

Cherry picked it and I was able to build it on arm64 and x86.

Cheers,
Anders
[1] http://ix.io/3sS6