Re: [PATCH 1/2] hugetlb, sysctl: pass '.extra1 = NULL' rather then '.extra1 = &zero'

From: David Rientjes
Date: Wed Dec 17 2014 - 19:38:16 EST


On Wed, 17 Dec 2014, Andrey Ryabinin wrote:

> Commit ed4d4902ebdd ("mm, hugetlb: remove hugetlb_zero and hugetlb_infinity") replaced
> 'unsigned long hugetlb_zero' with 'int zero' leading to out-of-bounds access
> in proc_doulongvec_minmax().
> Use '.extra1 = NULL' instead of '.extra1 = &zero'. Passing NULL is equivalent to
> passing minimal value, which is 0 for unsigned types.
>
> Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Suggested-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
> Fixes: ed4d4902ebdd ("mm, hugetlb: remove hugetlb_zero and hugetlb_infinity")
> Signed-off-by: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>

Acked-by: David Rientjes <rientjes@xxxxxxxxxx>

Patch title is a little awkward, though, maybe "mm, hugetlb: remove
unnecessary lower bound on sysctl handlers"?
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