Re: [git pull] core, x86: make LIST_POISON less deadly

[Linus Torvalds]

On Mon, 14 Jul 2008, Ingo Molnar wrote:
>  
> +config ILLEGAL_POINTER_VALUE
> +       hex
> +       default 0 if X86_32
> +       default 0xffffc10000000000 if X86_64

This looks like a singularly bad pointer value on x86-64.

Why not pick something that is *guaranteed* to fault? The above looks like 
any future setup that supports 41 bits of addressing and has extended the 
page tables (yes, it will happen eventually) will find that to be a 
perfectly valid address?

It's also visually confusing, since it's visually very close to a real 
kernel pointer too.

Grr.

Why not use something sane like 0xdead000000000000, which has the high bit 
set but very fundamentally isn't a valid pointer, and never will be? And 
which is a *lot* more visually obvious too!

		Linus
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