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Subject: Re: [PATCH v2 0/2] mm/kasan: dump alloc/free stack for page allocator
To:     Andrey Ryabinin <aryabinin@virtuozzo.com>,
        walter-zh.wu@mediatek.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>
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        linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
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References: <20190909082412.24356-1-walter-zh.wu@mediatek.com>
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From:   Vlastimil Babka <vbabka@suse.cz>
Message-ID: <4faedb4d-f16c-1917-9eaa-b0f9c169fa50@suse.cz>
Date:   Tue, 10 Sep 2019 13:53:23 +0200
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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