Re: make PROT_WRITE imply PROT_READ

From: Alan Cox
Date: Fri Jun 30 2006 - 08:03:15 EST


Ar Gwe, 2006-06-30 am 10:35 +0200, ysgrifennodd Arjan van de Ven:
> apps like JVM's forgot PROT_EXEC and break when the hardware enforces it
> apps that forget PROT_READ break when the kernel/hardware enforce it
>
> not too much difference....

There is quite a difference. The _EXEC case behaves predictably for the
platforms that support it. At least I am not aware of cases that is not
true. The _READ case without the fault handling patch behaves
unpredictably depending on the precise ordering of events on a clean
page.

Alan

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