Re: Process-shared futexes on hugepages puts the kernel in aninfinite loop in 2.6.32.11; is this fixed now?

[Andrea Arcangeli]

On Mon, Apr 19, 2010 at 06:18:48PM +0200, Peter Zijlstra wrote:
> Well, most poison values have that problem and still we have them. Also

That would better be fixed too to stay <4096 for higher chance of
bug-detection, it doesn't make this case correct ;).

> on 64bit machines you can use POISON_POINTER_DELTA to map it outside the
> virtual address range.

We've thousands of magic values there, I don't see much benefit from
POISON_POINTER_DELTA other than being able to call it
0xdeadbeef+POISON_POINTER_DELTA ;). We always look the assembly to
find the actual real raw pointer value (without the field offset) so I
think using a range between 0xaaa and 0xbbb for the error pointers, is
functional enough, but it's up to you as long as it is a address range
that can't be used by userland it's surely ok ;).
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