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Subject[PATCH][BUGFIX] vmscan: limit VM_EXEC protection to file pages
It is possible to have !Anon but SwapBacked pages, and some apps could
create huge number of such pages with MAP_SHARED|MAP_ANONYMOUS. These
pages go into the ANON lru list, and hence shall not be protected: we
only care mapped executable files. Failing to do so may trigger OOM.

Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
mm/vmscan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- linux.orig/mm/vmscan.c 2009-10-13 09:49:05.000000000 +0800
+++ linux/mm/vmscan.c 2009-10-13 09:49:37.000000000 +0800
@@ -1356,7 +1356,7 @@ static void shrink_active_list(unsigned
* IO, plus JVM can create lots of anon VM_EXEC pages,
* so we ignore them here.
*/
- if ((vm_flags & VM_EXEC) && !PageAnon(page)) {
+ if ((vm_flags & VM_EXEC) && page_is_file_cache(page)) {
list_add(&page->lru, &l_active);
continue;
}

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