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authorYinghai Lu <yinghai@kernel.org>2011-05-01 19:12:04 +0200
committerIngo Molnar <mingo@elte.hu>2011-05-01 19:15:11 +0200
commit2be19102b71c1a45d37fec50303791daa1a06869 (patch)
treeb6902dc6d25f3d99d047963f85ed7f15778a5c26
parente20a2d205c05cef6b5783df339a7d54adeb50962 (diff)
x86, NUMA: Fix empty memblk detection in numa_cleanup_meminfo()
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>
-rw-r--r--arch/x86/mm/numa_64.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index e8c00cc72033..85b52fc03084 100644
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -306,7 +306,7 @@ int __init numa_cleanup_meminfo(struct numa_meminfo *mi)
bi->end = min(bi->end, high);
/* and there's no empty block */
- if (bi->start == bi->end) {
+ if (bi->start >= bi->end) {
numa_remove_memblk_from(i--, mi);
continue;
}