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authorLi Zhong <zhong@linux.vnet.ibm.com>2014-08-06 16:07:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-08-06 18:01:21 -0700
commitd0177639310d23c7739500df3c6ce6fdfe34acec (patch)
treec67d79bed5c81e24e6bf616786b6f21726b4f4d4 /mm
parent8fe780484d2674eec27e12bb29c07d3e98a7ad21 (diff)
downloadlinux-d0177639310d23c7739500df3c6ce6fdfe34acec.tar.gz
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(). [rientjes@google.com: no legitimate reason to call dissolve_free_huge_pages() when !hugepages_supported()] Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> [3.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/hugetlb.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d9ad93b55585..eeceeeb09019 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1088,6 +1088,9 @@ void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
unsigned long pfn;
struct hstate *h;
+ if (!hugepages_supported())
+ return;
+
/* Set scan step to minimum hugepage size */
for_each_hstate(h)
if (order > huge_page_order(h))