Re: [PATCH] Make LIST_POISON less deadly

From: Ingo Molnar
Date: Mon May 19 2008 - 09:38:57 EST



* Avi Kivity <avi@xxxxxxxxxxxx> wrote:

>> i'd suggest to add an ARCH_ILLEGAL_POINTER define instead, which
>> defaults to zero and gets added to pointer-ish poison values. That
>> makes it both simpler and also it does not need any include/asm
>> changes because ARCH_ILLEGAL_POINTER can be set from the Kconfig
>> space.
>
> Right.
>
> How much unmapped space do we have on i386 or other archs? The deltas
> added to ARCH_ILLEGAL_POINTER will have to be limited to that.

can we get away with having the offset default to zero, and all poison
values remain unchanged if that? Then 64-bit x86 could just set the
offset to 2^63 and we wont have to worry about 32-bit x86 at all ...

i.e. start small with this and only have an effect on 64-bit x86.

Ingo
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