The patch titled
Subject: mm: fix potential infinite loop in dissolve_free_huge_pages()
has been added to the -mm tree. Its filename is
mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages.patch
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------------------------------------------------------
From: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
Subject: mm: fix potential infinite loop in dissolve_free_huge_pages()
It is possible for some platforms, such as powerpc to set HPAGE_SHIFT to 0
to indicate huge pages not supported.
When this is the case, hugetlbfs could be disabled during boot time:
hugetlbfs: disabling because there are no supported hugepage sizes
Then in dissolve_free_huge_pages(), order is kept maximum (64 for 64bits),
and the for loop below won't end: for (pfn = start_pfn; pfn < end_pfn; pfn
+= 1 << order)
As suggested by Naoya, below fix checks hugepages_supported() before
calling dissolve_free_huge_pages().
Signed-off-by: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [3.12+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN mm/memory_hotplug.c~mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages
+++ a/mm/memory_hotplug.c
@@ -1726,7 +1726,8 @@ repeat:
* dissolve free hugepages in the memory block before doing offlining
* actually in order to make hugetlbfs's object counting consistent.
*/
- dissolve_free_huge_pages(start_pfn, end_pfn);
+ if (hugepages_supported())
+ dissolve_free_huge_pages(start_pfn, end_pfn);
/* check again */
offlined_pages = check_pages_isolated(start_pfn, end_pfn);
if (offlined_pages < 0) {
_
Patches currently in -mm which might be from zhong@xxxxxxxxxxxxxxxxxx are
mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages.patch
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