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    SubjectRe: [PATCH] kdump: force page alignment for per-CPU crash notes.
    On Wed, Feb 29, 2012 at 05:23:10PM -0800, Eugene Surovegin wrote:
    > On Wed, Feb 29, 2012 at 5:18 PM, Simon Horman <horms@verge.net.au> wrote:
    >
    > > On Wed, Feb 29, 2012 at 09:21:23AM -0800, Eugene Surovegin wrote:
    > > > Per-CPU allocations are not guaranteed to be physically contiguous.
    > > > However, kdump kernel and user-space code assumes that per-CPU
    > > > memory, used for saving CPU registers on crash, is.
    > > > This can cause corrupted /proc/vmcore in some cases - the main
    > > > symptom being huge ELF note section.
    > > >
    > > > Force page alignment for note_buf_t to ensure that this assumption holds.
    > >
    > > Ouch. I'm surprised there is an allocation on crash, perhaps
    > > it could at least be done earlier? And am I right in thinking
    > > that this change increases the likely hood that the allocation
    > > could fail?
    > >
    >
    > I'm not following. This allocation is done on start-up, not on crash.
    > If you cannot allocate this much memory on system boot, I'm not sure what
    > else you can do on this system....

    Sorry, my eyes deceived me. You are correct and I agree.

    Is it the case that note_buf_t is never larger than PAGE_SIZE?
    If so I your patch looks good to me.


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