Re: 4.4-rc5: ugly warn on: 5 W+X pages found

From: Arjan van de Ven
Date: Tue Dec 15 2015 - 08:30:34 EST


On 12/14/2015 11:56 PM, Pavel Machek wrote:
On Mon 2015-12-14 13:24:08, Arjan van de Ven wrote:

That's weird. The only API to do that seems to be manually setting
kmap_prot to _PAGE_KERNEL_EXEC, and nothing does that. (Why is
kmap_prot a variable on x86 at all? It has exactly one writer, and
that's the code that initializes it in the first place. Shouldn't we
#define kmap_prot _PAGE_KERNEL?

iirc it changes based on runtime detection of NX capability

Huh. Is it possible that core duo is so old that it has no NX?

really stupid question I guess, but is PAE on ?
(64 bit pagetables are required for NX)


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