Re: [PATCH 2/3] x86: set_personality_ia32() abuses TS_COMPAT

[Linus Torvalds]

On Tue, 16 Feb 2010, Oleg Nesterov wrote:
> 
> and, following this logic, shouldn't set_personality_64bit() clear
> TS_COMPAT ?

Yes, I think it should. If we come from a 32-bit environment, and execute 
a 64-bit binary, I think the execve() environment of the new 64-bit binary 
should be _exactly_ the same as if it was executed from a 64-bit one.

Of course, it's entirely possible that TS_COMPAT simply doesn't matter at 
all in either context, but I do think that we should strive for "the 
binary does exactly the same regardless of whether it was started from 
a 32-bit or a 64-bit binary".

And the best way to guarantee that is to make sure that we really do set 
the environment to the same thing. So yes, set_personality_64bit() should 
clear all the 32-bit compat bits.

		Linus
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