linux-kernel - Re: [PATCH] [v3] kasan: avoid -Wmaybe-uninitialized warning

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Message-ID: <467b0241-da9a-6e91-d7be-b72618a24306@virtuozzo.com>
Date:   Tue, 25 Jul 2017 18:31:23 +0300
From:   Andrey Ryabinin <aryabinin@...tuozzo.com>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Dmitry Vyukov <dvyukov@...gle.com>,
        Alexander Potapenko <glider@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andrey Konovalov <andreyknvl@...gle.com>,
        Mark Rutland <mark.rutland@....com>,
        kasan-dev@...glegroups.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [v3] kasan: avoid -Wmaybe-uninitialized warning

On 07/25/2017 06:27 PM, Arnd Bergmann wrote:
> gcc-7 produces this warning:
> 
> mm/kasan/report.c: In function 'kasan_report':
> mm/kasan/report.c:351:3: error: 'info.first_bad_addr' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>    print_shadow_for_address(info->first_bad_addr);
>    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> mm/kasan/report.c:360:27: note: 'info.first_bad_addr' was declared here
> 
> The code seems fine as we only print info.first_bad_addr when there is a shadow,
> and we always initialize it in that case, but this is relatively hard
> for gcc to figure out after the latest rework. Adding an intialization
> to the most likely value together with the other struct members
> shuts up that warning.
> 
> Fixes: b235b9808664 ("kasan: unify report headers")
> Link: https://patchwork.kernel.org/patch/9641417/
> Suggested-by: Alexander Potapenko <glider@...gle.com>
> Suggested-by: Andrey Ryabinin <aryabinin@...tuozzo.com>
> Cc: Dmitry Vyukov <dvyukov@...gle.com>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---

Acked-by: Andrey Ryabinin <aryabinin@...tuozzo.com>