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Subject: Re: [PATCH 2/2] kasan: disallow compiler to optimize away memset in
 tests
References: <cover.1519924383.git.andreyknvl@google.com>
 <105ec9a308b2abedb1a0d1fdced0c22d765e4732.1519924383.git.andreyknvl@google.com>
From: Andrey Ryabinin <aryabinin@virtuozzo.com>
Message-ID: <41d0e9bd-9102-6a50-e0d6-c193696381c9@virtuozzo.com>
Date: Fri, 2 Mar 2018 15:11:56 +0300
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In-Reply-To: <105ec9a308b2abedb1a0d1fdced0c22d765e4732.1519924383.git.andreyknvl@google.com>
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To: Andrey Konovalov <andreyknvl@google.com>, Alexander Potapenko <glider@google.com>, Dmitry Vyukov <dvyukov@google.com>, Andrew Morton <akpm@linux-foundation.org>, Geert Uytterhoeven <geert@linux-m68k.org>, Nick Terrell <terrelln@fb.com>, Chris Mason <clm@fb.com>, Yury Norov <ynorov@caviumnetworks.com>, Al Viro <viro@zeniv.linux.org.uk>, "Luis R . Rodriguez" <mcgrof@kernel.org>, Palmer Dabbelt <palmer@dabbelt.com>, "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>, Jeff Layton <jlayton@redhat.com>, "Jason A . Donenfeld" <Jason@zx2c4.com>, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org
Cc: Kostya Serebryany <kcc@google.com>



On 03/01/2018 08:15 PM, Andrey Konovalov wrote:
> A compiler can optimize away memset calls by replacing them with mov
> instructions. There are KASAN tests, that specifically test that KASAN
> correctly handles memset calls, we don't want this optimization to
> happen.
> 
> The solution is to add -fno-builtin flag to test_kasan.ko
> 
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

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

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