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    SubjectRe: [RFC/PATCH RESEND -next 00/21] Address sanitizer for kernel (kasan) - dynamic memory error detector.
    On 07/10/14 01:59, Vegard Nossum wrote:
    > On 9 July 2014 23:44, Andi Kleen <andi@firstfloor.org> wrote:
    >> Dave Hansen <dave.hansen@intel.com> writes:
    >>>
    >>> You're also claiming that "KASAN is better than all of
    >>
    >> better as in finding more bugs, but surely not better as in
    >> "do so with less overhead"
    >>
    >>> CONFIG_DEBUG_PAGEALLOC". So should we just disallow (or hide)
    >>> DEBUG_PAGEALLOC on kernels where KASAN is available?
    >>
    >> I don't think DEBUG_PAGEALLOC/SLUB debug and kasan really conflict.
    >>
    >> DEBUG_PAGEALLOC/SLUB is "much lower overhead but less bugs found".
    >> KASAN is "slow but thorough" There are niches for both.
    >>
    >> But I could see KASAN eventually deprecating kmemcheck, which
    >> is just incredible slow.
    >
    > FWIW, I definitely agree with this -- if KASAN can do everything that
    > kmemcheck can, it is no doubt the right way forward.
    >

    AFAIK kmemcheck could catch reads of uninitialized memory.
    KASAN can't do it now, but It should be possible to implementation.
    There is such tool for userspace - https://code.google.com/p/memory-sanitizer/wiki/MemorySanitizer

    However detection of reads of uninitialized memory will require a different
    shadow encoding. Therefore I think it would be better to make it as a separate feature, incompatible with kasan.



    >
    > Vegard
    >



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