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 <[email protected]> know about it.


>From d0177639310d23c7739500df3c6ce6fdfe34acec Mon Sep 17 00:00:00 2001
From: Li Zhong <[email protected]>
Date: Wed, 6 Aug 2014 16:07:56 -0700
Subject: mm: fix potential infinite loop in dissolve_free_huge_pages()

From: Li Zhong <[email protected]>

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().

[[email protected]: no legitimate reason to call dissolve_free_huge_pages() 
when !hugepages_supported()]
Signed-off-by: Li Zhong <[email protected]>
Acked-by: Naoya Horiguchi <[email protected]>
Acked-by: David Rientjes <[email protected]>
Signed-off-by: David Rientjes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 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 [email protected] 
are

queue-3.16/mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages.patch
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