From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>

With list poisoning on by default from linux-2.6.7, it's easier than ever to
trigger the bug in try_to_free_low().  It ought to use the safe version of
list iterater.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>