---

yaml --- r: 190196 b: refs/heads/master c: 23be746 h: refs/heads/master v: v3
git-mirror · Apr 24, 2010 · d0d620f · d0d620f
1 parent ce66d2d
commit d0d620f
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Showing 3 changed files with 14 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9a6a1ecd9e9b5d046a236da2f7eb6b6812f04229
+refs/heads/master: 23be7468e8802a2ac1de6ee3eecb3ec7f14dc703
diff --git a/trunk/include/linux/poison.h b/trunk/include/linux/poison.h
@@ -48,6 +48,15 @@
 #define POISON_FREE	0x6b	/* for use-after-free poisoning */
 #define	POISON_END	0xa5	/* end-byte of poisoning */
 
+/********** mm/hugetlb.c **********/
+/*
+ * Private mappings of hugetlb pages use this poisoned value for
+ * page->mapping. The core VM should not be doing anything with this mapping
+ * but futex requires the existence of some page->mapping value even though it
+ * is unused if PAGE_MAPPING_ANON is set.
+ */
+#define HUGETLB_POISON	((void *)(0x00300300 + POISON_POINTER_DELTA + PAGE_MAPPING_ANON))
+
 /********** arch/$ARCH/mm/init.c **********/
 #define POISON_FREE_INITMEM	0xcc
 

diff --git a/trunk/mm/hugetlb.c b/trunk/mm/hugetlb.c
@@ -546,6 +546,7 @@ static void free_huge_page(struct page *page)
 
 	mapping = (struct address_space *) page_private(page);
 	set_page_private(page, 0);
+	page->mapping = NULL;
 	BUG_ON(page_count(page));
 	INIT_LIST_HEAD(&page->lru);
 
@@ -2447,8 +2448,10 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
 			spin_lock(&inode->i_lock);
 			inode->i_blocks += blocks_per_huge_page(h);
 			spin_unlock(&inode->i_lock);
-		} else
+		} else {
 			lock_page(page);
+			page->mapping = HUGETLB_POISON;
+		}
 	}
 
 	/*