[PATCH] arm64: enable PTE type bit in the mask for pte_modify

Catalin Marinas catalin.marinas at arm.com
Wed Feb 25 08:43:20 PST 2015

On Tue, Feb 24, 2015 at 03:40:21PM -0800, Feng Kan wrote:
> Caught during Trinity testing. The pte_modify does not allow
> modification for PTE type bit. This cause the test to hang
> the system. It is found that the PTE can't transit from an
> inaccessible page (b00) to a valid page (b11) because the mask
> does not allow it. This happens when a big block of mmaped
> memory is set the PROT_NONE, then the a small piece is broken
> off and set to PROT_WRITE | PROT_READ cause a huge page split.
> Signed-off-by: Feng Kan <fkan at apm.com>

It looks fine to me. Thanks.

I wonder whether mprotect() to change between PROT_NONE and an
accessible protection ever worked (I thought we tested this).


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