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author | Yinghai Lu <yinghai@kernel.org> | 2011-05-01 19:12:04 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2011-05-01 19:15:11 +0200 |
commit | 2be19102b71c1a45d37fec50303791daa1a06869 (patch) | |
tree | b6902dc6d25f3d99d047963f85ed7f15778a5c26 /arch/x86/mm | |
parent | e20a2d205c05cef6b5783df339a7d54adeb50962 (diff) | |
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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>
Diffstat (limited to 'arch/x86/mm')
-rw-r--r-- | arch/x86/mm/numa_64.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c index e8c00cc..85b52fc 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; } |