linux-kernel - Re: [PATCH] video: fbdev: pvr2fb: initialize variables

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Message-ID: <CAK8P3a15yTNgDrLWB4mhTJfjLjxjexbGg4Har4S1Q9uUfCBgFw@mail.gmail.com>
Date:   Mon, 20 Jul 2020 21:27:25 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     trix@...hat.com
Cc:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        John Hubbard <jhubbard@...dia.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>,
        Jani Nikula <jani.nikula@...el.com>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Fbdev development list <linux-fbdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] video: fbdev: pvr2fb: initialize variables

On Mon, Jul 20, 2020 at 9:19 PM <trix@...hat.com> wrote:
>
> From: Tom Rix <trix@...hat.com>
>
> clang static analysis reports this repesentative error
>
> pvr2fb.c:1049:2: warning: 1st function call argument
>   is an uninitialized value [core.CallAndMessage]
>         if (*cable_arg)
>         ^~~~~~~~~~~~~~~
>
> Problem is that cable_arg depends on the input loop to
> set the cable_arg[0].  If it does not, then some random
> value from the stack is used.
>
> A similar problem exists for output_arg.
>
> So initialize cable_arg and output_arg.

Adding a zero-initialization is almost never the correct way to
deal with these warnings, so one has to be careful doing this.

I checked this file, and your patch is absolutely correct here. ;-)

> Signed-off-by: Tom Rix <trix@...hat.com>

Acked-by: Arnd Bergmann <arnd@...db.de>