The code to detect IO links on Opteron would not check
if the node had actually memory. This could lead to pci_bus_to_node
returning an invalid node, which might cause crashes later
when dma_alloc_coherent passes it to page_alloc_node().

The bug has been there forever but for some reason
it is causing now crashes.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>