Re: make PROT_WRITE imply PROT_READ

[Jason Baron]

On Fri, 23 Jun 2006, Arjan van de Ven wrote:

> 
> > 
> > hi,
> > 
> > So if i create a PROT_WRITE only mapping and then read from first and then 
> > writte to it a get a SEGV. However, if i write to it first and then read 
> > from it, i don't get a SEGV...Why should the read/write ordering matter? 
> 
> it matters only on those cpus that don't have explicit/separate read
> permissions (just like PROT_EXEC is implied on cpus that don't have a
> special permission bit for that)...
> 
> 
> 

i understand that, but i'd like to see it changed so that i don't get a 
SEGV when i read first on those cpus. The current behavior, besides being 
inconsistent, is rather confusing...in addition, if ptes are copied 
instead of faulted i get yet another type of behavior...

-Jason

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