Re: [patch] mm: sparsemem memory_present() memory corruption fix

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxx> wrote:

> finally found it ... the patch below solves the sparsemem crash and 
> the testsystem boots up fine now:
> 
>   mars:~> uname -a
>   Linux mars 2.6.25-rc9-sched-devel.git-x86-latest.git #985 SMP Wed Apr 16 
>   01:37:37 CEST 2008 i686 i686 i386 GNU/Linux

i re-checked the original SLAB config too and that boots fine as well 
now - so i'm confident that the regression has been sufficiently cured.

it's getting quite late here (or rather, it's getting early :-/ ) so it 
would be nice if others could double-check this calculation (with an eye 
on all possible architectures):

+       unsigned long max_arch_pfn = 1ULL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);

and also check my analysis whether it is correct and whether it matches 
the reported bug patterns. But otherwise the fix looks like a safe fix 
for v2.6.25-final to me - it only filters out values from sparsemem 
input that are nonsensical in the sparsemem framework anyway.

	Ingo
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