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authorAndy Whitcroft <apw@shadowen.org>2008-02-23 18:23:32 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-23 20:12:13 -0500
commite5df70ab194543522397fa3da8c8f80564a0f7d3 (patch)
tree1a4354932196a1611752032362689bd404836af8 /mm/hugetlb.c
parent745329c4a2a25efbf5ba6cd7842e07840e4e9775 (diff)
hugetlb: ensure we do not reference a surplus page after handing it to buddy
When we free a page via free_huge_page and we detect that we are in surplus the page will be returned to the buddy. After this we no longer own the page. However at the end free_huge_page we clear out our mapping pointer from page private. Even where the page is not a surplus we free the page to the hugepage pool, drop the pool locks and then clear page private. In either case the page may have been reallocated. BAD. Make sure we clear out page private before we free the page. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Adam Litke <agl@us.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index cb1b3a7ecdf..89e6286a7f5 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -120,6 +120,7 @@ static void free_huge_page(struct page *page)
120 struct address_space *mapping; 120 struct address_space *mapping;
121 121
122 mapping = (struct address_space *) page_private(page); 122 mapping = (struct address_space *) page_private(page);
123 set_page_private(page, 0);
123 BUG_ON(page_count(page)); 124 BUG_ON(page_count(page));
124 INIT_LIST_HEAD(&page->lru); 125 INIT_LIST_HEAD(&page->lru);
125 126
@@ -134,7 +135,6 @@ static void free_huge_page(struct page *page)
134 spin_unlock(&hugetlb_lock); 135 spin_unlock(&hugetlb_lock);
135 if (mapping) 136 if (mapping)
136 hugetlb_put_quota(mapping, 1); 137 hugetlb_put_quota(mapping, 1);
137 set_page_private(page, 0);
138} 138}
139 139
140/* 140/*