This is a note to let you know that I've just added the patch titled
mm: fix potential infinite loop in dissolve_free_huge_pages()
to the 3.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages.patch
and it can be found in the queue-3.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d0177639310d23c7739500df3c6ce6fdfe34acec Mon Sep 17 00:00:00 2001
From: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
Date: Wed, 6 Aug 2014 16:07:56 -0700
Subject: mm: fix potential infinite loop in dissolve_free_huge_pages()
From: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
commit d0177639310d23c7739500df3c6ce6fdfe34acec upstream.
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@xxxxxxxxxx: no legitimate reason to call dissolve_free_huge_pages() when !hugepages_supported()]
Signed-off-by: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1089,6 +1089,9 @@ void dissolve_free_huge_pages(unsigned l
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))
Patches currently in stable-queue which might be from zhong@xxxxxxxxxxxxxxxxxx are
queue-3.16/mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages.patch
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