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    SubjectRe: WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (f6f6e1a4), by kmemleak's scan_block()
    On Tue, 2009-08-25 at 10:11 +0100, Catalin Marinas wrote:
    > Yes, that's possible.
    > Does kmemcheck work on a page-range basis. If an object doesn't cross
    > page boundaries, would it be considered fully initialised after writing
    > a single location?
    > > I think it would be better to ask kmemcheck on a per-pointer basis
    > > (i.e. for each pointer-sized word in the object), whether it is
    > > initialized or not.
    > This should work but how expensive is this check?

    Everything in kmemcheck is expensive :-). kmemcheck_shadow_lookup()
    needs to do PTE lookup to find the shadow page where we record object
    states. I'm not sure why that's a problem, though. If you've enabled
    kmemcheck, everything is already dead slow and kmemleak scanning happens
    in background, no? Furthermore, I think we need to do it the way Vegard
    suggested to avoid false positives.


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