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    SubjectRe: [PATCH] eCryptfs - use page_alloc not kmalloc to get a page of memory
    Andrew Morton wrote:
    > On Mon, 28 Jul 2008 11:13:03 -0500
    > Eric Sandeen <sandeen@redhat.com> wrote:
    >
    >> With SLUB debugging turned on in 2.6.26, I was getting memory corruption
    >> when testing eCryptfs. The root cause turned out to be that eCryptfs
    >> was doing kmalloc(PAGE_CACHE_SIZE); virt_to_page() and treating that
    >> as a nice page-aligned chunk of memory. But at least with SLUB debugging
    >> on, this is not always true, and the page we get from virt_to_page does
    >> not necessarily match the PAGE_CACHE_SIZE worth of memory we got from
    >> kmalloc.
    >>
    >> My simple testcase was 2 loops doing "rm -f fileX; cp /tmp/fileX ." for
    >> 2 different multi-megabyte files. With this change I no longer see
    >> the corruption.
    >
    > The fix applies to both 2.6.25 and to 2.6.26 and appears to be needed
    > in both kernel versions, so I have tagged it for backporting into both.

    I agree, thanks.

    -Eric


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