Re: 2.6.25-git2: BUG: unable to handle kernel paging request atffffffffffffffff

[Linus Torvalds]

On Thu, 24 Apr 2008, David Miller wrote:
> 
> So the clue is setting some byte at ((offset % 8) == 0) into a
> structure with 0xf0...

It's not always at (offset % 8) == 0. We've seen that 0xf0 pattern in 
other oopses, but it's not always 8-byte aligned. In fact, when we've seen 
it in oopses, it has generally been in the higher bytes (eg offset 5 
within a 64-bit word, causing an invalid pointer on x86-64).

But that 0xf0 definitely has shown up before. It's not the *only* 
corruption, but it's definitely a very interesting pattern. And the other 
ones that didn't show the 0xf0 pattern could obviously be due to pointers 
that were corrupted by 0xf0 in low bytes, so it _may_ be the source of the 
other corruptions too that didn't have an obvious 0xf0 directly in them.

			Linus
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