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| author | Li Zhong <zhong@linux.vnet.ibm.com> | 2014-08-07 01:07:56 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-07 03:01:21 +0200 |
| commit | d0177639310d23c7739500df3c6ce6fdfe34acec (patch) | |
| tree | c67d79bed5c81e24e6bf616786b6f21726b4f4d4 | |
| parent | mm, thp: restructure thp avoidance of light synchronous migration (diff) | |
| download | linux-d0177639310d23c7739500df3c6ce6fdfe34acec.tar.xz linux-d0177639310d23c7739500df3c6ce6fdfe34acec.zip | |
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>
| -rw-r--r-- | mm/hugetlb.c | 3 |
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)) |