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2be19102b7
numa_cleanup_meminfo() trims each memblk between low (0) and high (max_pfn) limits and discards empty ones. However, the emptiness detection incorrectly used equality test. If the start of a memblk is higher than max_pfn, it is empty but fails the equality test and doesn't get discarded. The condition triggers when max_pfn is lower than start of a NUMA node and results in memory misconfiguration - leading to WARN_ON()s and other funnies. The bug was discovered in devel branch where 32bit too uses this code path for NUMA init. If a node is above the addressing limit, max_pfn ends up lower than the node triggering this problem. The failure hasn't been observed on x86-64 but is still possible with broken hardware e820/NUMA info. As the fix is very low risk, it would be better to apply it even for 64bit. Fix it by using >= instead of ==. Signed-off-by: Yinghai Lu <yinghai@kernel.org> [ Extracted the actual fix from the original patch and rewrote patch description. ] Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/20110501171204.GO29280@htj.dyndns.org Signed-off-by: Ingo Molnar <mingo@elte.hu>