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Message-ID: <1568119549.24886.18.camel@mtksdccf07>
Subject: Re: [PATCH v2 0/2] mm/kasan: dump alloc/free stack for page
 allocator
From:   Walter Wu <walter-zh.wu@mediatek.com>
To:     Vlastimil Babka <vbabka@suse.cz>
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>,
        Will Deacon <will@kernel.org>,
        "Andrey Konovalov" <andreyknvl@google.com>,
        Arnd Bergmann <arnd@arndb.de>,
        "Thomas Gleixner" <tglx@linutronix.de>,
        Michal Hocko <mhocko@kernel.org>, Qian Cai <cai@lca.pw>,
        <linux-kernel@vger.kernel.org>, <kasan-dev@googlegroups.com>,
        <linux-mm@kvack.org>, <linux-arm-kernel@lists.infradead.org>,
        <linux-mediatek@lists.infradead.org>, <wsd_upstream@mediatek.com>
Date:   Tue, 10 Sep 2019 20:45:49 +0800
In-Reply-To: <4faedb4d-f16c-1917-9eaa-b0f9c169fa50@suse.cz>
References: <20190909082412.24356-1-walter-zh.wu@mediatek.com>
         <d53d88df-d9a4-c126-32a8-4baeb0645a2c@suse.cz>
         <a7863965-90ab-5dae-65e7-8f68f4b4beb5@virtuozzo.com>
         <4faedb4d-f16c-1917-9eaa-b0f9c169fa50@suse.cz>
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On Tue, 2019-09-10 at 13:53 +0200, Vlastimil Babka wrote:
> On 9/10/19 12:50 PM, Andrey Ryabinin wrote:
> > 
> > 
> > For slab objects we memorize both alloc and free stacks. You'll never know in advance what information will be usefull
> > to fix an issue, so it usually better to provide more information. I don't think we should do anything different for pages.
> 
> Exactly, thanks.
> 
> > Given that we already have the page_owner responsible for providing alloc/free stacks for pages, all that we should in KASAN do is to
> > enable the feature by default. Free stack saving should be decoupled from debug_pagealloc into separate option so that it can be enabled
> > by KASAN and/or debug_pagealloc.
> 
> Right. Walter, can you do it that way, or should I?
> 
> Thanks,
> Vlastimil

I will send new patch v3.