The patch titled
2.6.25-rc3-mm1 kernel bug while running libhugetlbfs
has been added to the -mm tree. Its filename is
hugetlb-correct-page-count-for-surplus-huge-pages-fix.patch
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See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: 2.6.25-rc3-mm1 kernel bug while running libhugetlbfs
From: Adam Litke <agl@xxxxxxxxxx>
On Tue, 2008-03-04 at 11:51 -0800, Andrew Morton wrote:
> hugetlb-correct-page-count-for-surplus-huge-pages.patch adds:
>
> if (page) {
> /*
> * This page is now managed by the hugetlb allocator and has
> * no users -- drop the buddy allocator's reference.
> */
> int page_count = put_page_testzero(page);
> BUG_ON(page_count != 0);
>
>
Ugh I got bitten by put_page_testzero(). When it returns 1, the page
count is zero (not the page count).
My initial version had a BUG_ON() with side-effects. When a reviewer
pointed it out, I thought I could fix the patch up on its way out the
door. I have self-administered my punishment. This patch will fix it:
Signed-off-by: Adam Litke <agl@xxxxxxxxxx>
Cc: Kamalesh Babulal <kamalesh@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN mm/hugetlb.c~hugetlb-correct-page-count-for-surplus-huge-pages-fix mm/hugetlb.c
--- a/mm/hugetlb.c~hugetlb-correct-page-count-for-surplus-huge-pages-fix
+++ a/mm/hugetlb.c
@@ -290,8 +290,8 @@ static struct page *alloc_buddy_huge_pag
* This page is now managed by the hugetlb allocator and has
* no users -- drop the buddy allocator's reference.
*/
- int page_count = put_page_testzero(page);
- BUG_ON(page_count != 0);
+ put_page_testzero(page);
+ VM_BUG_ON(page_count(page));
nid = page_to_nid(page);
set_compound_page_dtor(page, free_huge_page);
/*
_
Patches currently in -mm which might be from agl@xxxxxxxxxx are
hugetlb-close-a-difficult-to-trigger-reservation-race.patch
hugetlb-fix-pool-shrinking-while-in-restricted-cpuset.patch
hugetlb-correct-page-count-for-surplus-huge-pages.patch
hugetlb-correct-page-count-for-surplus-huge-pages-fix.patch
hugetlb-decrease-hugetlb_lock-cycling-in-gather_surplus_huge_pages.patch
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