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Message-ID: <1567606591.32522.21.camel@mtksdccf07>
Subject: Re: [PATCH 1/2] mm/kasan: dump alloc/free stack for page allocator
From:   Walter Wu <walter-zh.wu@mediatek.com>
To:     Andrey Konovalov <andreyknvl@google.com>
CC:     Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Martin Schwidefsky" <schwidefsky@de.ibm.com>,
        Arnd Bergmann <arnd@arndb.de>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        <linux-mediatek@lists.infradead.org>, <wsd_upstream@mediatek.com>
Date:   Wed, 4 Sep 2019 22:16:31 +0800
In-Reply-To: <CAAeHK+wyvLF8=DdEczHLzNXuP+oC0CEhoPmp_LHSKVNyAiRGLQ@mail.gmail.com>
References: <20190904065133.20268-1-walter-zh.wu@mediatek.com>
         <CAAeHK+wyvLF8=DdEczHLzNXuP+oC0CEhoPmp_LHSKVNyAiRGLQ@mail.gmail.com>
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On Wed, 2019-09-04 at 15:44 +0200, Andrey Konovalov wrote:
> On Wed, Sep 4, 2019 at 8:51 AM Walter Wu <walter-zh.wu@mediatek.com> wrote:
> > +config KASAN_DUMP_PAGE
> > +       bool "Dump the page last stack information"
> > +       depends on KASAN && PAGE_OWNER
> > +       help
> > +         By default, KASAN doesn't record alloc/free stack for page allocator.
> > +         It is difficult to fix up page use-after-free issue.
> > +         This feature depends on page owner to record the last stack of page.
> > +         It is very helpful for solving the page use-after-free or out-of-bound.
> 
> I'm not sure if we need a separate config for this. Is there any
> reason to not have this enabled by default?

PAGE_OWNER need some memory usage, it is not allowed to enable by
default in low RAM device. so I create new feature option and the person
who wants to use it to enable it.

Thanks.
Walter