Re: [PATCH] Alternate futex non-page-pinning and COW fix

[Linus Torvalds]

On Thu, 4 Sep 2003, Linus Torvalds wrote:
> 
> Oh. I see. Yes - it's accessing "vm_flags" with "MAP_SEM". That's really 
> wrong, since it's not even the same _domain_. 

How about something like this that at least gets it closer? It fixes the
fact that incorrect usage of PROT_SEM would allow users to set the
VM_SHARED bit behind the back of the OS, which sounds like a total
disaster and which can potentially confuse other parts of the VM.

It's not a very _pretty_ fix, but there really is no excuse for PROT_xxx
to not match VM_xxx for the three standard protection flags, so in that
sense it is the technically "sane" approach. We might want to just
simplify the mmap() code too..

		Linus

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