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    SubjectRe: [PATCH 1/2] mm/kasan: dump alloc/free stack for page allocator
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    On Wed, 2019-09-04 at 14:49 +0200, Vlastimil Babka wrote:
    > On 9/4/19 8:51 AM, Walter Wu wrote:
    > > This patch is KASAN report adds the alloc/free stacks for page allocator
    > > in order to help programmer to see memory corruption caused by page.
    > >
    > > 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 pages.
    > > It is very helpful for solving the page use-after-free or out-of-bound.
    > >
    > > KASAN report will show the last stack of page, it may be:
    > > a) If page is in-use state, then it prints alloc stack.
    > > It is useful to fix up page out-of-bound issue.
    >
    > I expect this will conflict both in syntax and semantics with my series [1] that
    > adds the freeing stack to page_owner when used together with debug_pagealloc,
    > and it's now in mmotm. Glad others see the need as well :) Perhaps you could
    > review the series, see if it fulfils your usecase (AFAICS the series should be a
    > superset, by storing both stacks at once), and perhaps either make KASAN enable
    > debug_pagealloc, or turn KASAN into an alternative enabler of the functionality
    > there?
    >
    > Thanks, Vlastimil
    >
    > [1] https://lore.kernel.org/linux-mm/20190820131828.22684-1-vbabka@suse.cz/t/#u
    >
    Thanks your information.
    We focus on the smartphone, so it doesn't enable
    CONFIG_TRANSPARENT_HUGEPAGE, Is it invalid for our usecase?
    And It looks like something is different, because we only need last
    stack of page, so it can decrease memory overhead.
    I will try to enable debug_pagealloc(with your patch) and KASAN, then we
    see the result.

    Thanks.
    Walter

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