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From:   Qian Cai <cai@lca.pw>
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Subject: Re: [PATCH] kasan: fix the missing underflow in memmove and memcpy with CONFIG_KASAN_GENERIC=y
Date:   Tue, 8 Oct 2019 05:47:30 -0400
Message-Id: <B53A3CC0-CEA6-4E1C-BC38-19315D949F38@lca.pw>
References: <1570515358.4686.97.camel@mtksdccf07>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux-MM <linux-mm@kvack.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        linux-mediatek@lists.infradead.org,
        wsd_upstream <wsd_upstream@mediatek.com>
In-Reply-To: <1570515358.4686.97.camel@mtksdccf07>
To:     Walter Wu <walter-zh.wu@mediatek.com>
Sender: linux-kernel-owner@vger.kernel.org
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> On Oct 8, 2019, at 2:16 AM, Walter Wu <walter-zh.wu@mediatek.com> wrote:
>=20
> It is an undefined behavior to pass a negative numbers to
>    memset()/memcpy()/memmove(), so need to be detected by KASAN.

Why can=E2=80=99t this be detected by UBSAN?=