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Subject[PATCH] mm: add gfp mask checking for __get_free_pages()
__get_free_pages() with __GFP_HIGHMEM is not safe because the return
address cannot represent a highmem page. get_zeroed_page() already has
such a debug checking.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
---
mm/page_alloc.c | 24 +++++++++---------------
1 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e0f2cdf..4a1a374 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1903,31 +1903,25 @@ EXPORT_SYMBOL(__alloc_pages_nodemask);
*/
unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
{
- struct page * page;
+ struct page *page;
+
+ /*
+ * __get_free_pages() returns a 32-bit address, which cannot represent
+ * a highmem page
+ */
+ VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
+
page = alloc_pages(gfp_mask, order);
if (!page)
return 0;
return (unsigned long) page_address(page);
}
-
EXPORT_SYMBOL(__get_free_pages);

unsigned long get_zeroed_page(gfp_t gfp_mask)
{
- struct page * page;
-
- /*
- * get_zeroed_page() returns a 32-bit address, which cannot represent
- * a highmem page
- */
- VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
-
- page = alloc_pages(gfp_mask | __GFP_ZERO, 0);
- if (page)
- return (unsigned long) page_address(page);
- return 0;
+ return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
}
-
EXPORT_SYMBOL(get_zeroed_page);

void __pagevec_free(struct pagevec *pvec)
--
1.6.0.6


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