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

[Ingo Molnar <mingo@elte.hu>]

* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Mon, 14 Jul 2008, Avi Kivity wrote:
> > 
> > We could add a printk to the #GP handler that alerts the reader that a
> > poisoned list is suspected, if we find the address pattern in one of the
> > registers.
> 
> I wouldn't worry too much - it's going to be pretty visible anyway.
> 
> The only thing I _would_ worry about is the AMD prefetch bug - some AMD 
> cores raise a spurious page fault for prefetch instructions, and we ignore 
> it.
> 
> I _think_ that bug is a pure TLB issue and would never trigger for an 
> address that doesn't do page fault handling at all because it gets caught 
> in the "is the address valid" code, but it does make me go "Hmm".
> 
> See
> 
> 	http://lkml.org/lkml/2003/9/10/397
> 
> from Rich Brunner. The AMD errata listing does say just page fault, 
> and does talk about speculative TLB reloads, so I think we're all 
> good.

one of my testboxes has this erratum and i saw related bugs in the past 
during stress-tests so it will show up if the non-canonical address 
causes any problems. So i think 0xdead000000000000 will be fine, and 
even if it isnt, we'll catch any problems fast enough.

	Ingo