Messages in this thread | | | Subject | Re: make PROT_WRITE imply PROT_READ | From | Arjan van de Ven <> | Date | Fri, 23 Jun 2006 16:18:00 +0200 |
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On Fri, 2006-06-23 at 10:05 -0400, Jason Baron wrote: > 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. ?
why? You asked for this you get it in all cases we can deliver what you asked...
> 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...
same for prefault I suppose, but still.
you ask for it, and the kernel is supposed to deliver the best behavior it can.
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