kmemcheck: add hooks for the page allocator

This adds support for tracking the initializedness of memory that
was allocated with the page allocator. Highmem requests are not
tracked.

Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>

[build fix for !CONFIG_KMEMCHECK]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

1 files changed, 32 insertions, 13 deletions

diff --git a/mm/kmemcheck.c b/mm/kmemcheck.c
index eaa41b802611..fd814fd61319 100644
--- a/mm/kmemcheck.c
+++ b/mm/kmemcheck.c
@@ -1,10 +1,10 @@
+#include <linux/gfp.h>
 #include <linux/mm_types.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/kmemcheck.h>
 
-void kmemcheck_alloc_shadow(struct kmem_cache *s, gfp_t flags, int node,
-			   struct page *page, int order)
+void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
 {
 	struct page *shadow;
 	int pages;
@@ -16,7 +16,7 @@ void kmemcheck_alloc_shadow(struct kmem_cache *s, gfp_t flags, int node,
 	 * With kmemcheck enabled, we need to allocate a memory area for the
 	 * shadow bits as well.
 	 */
-	shadow = alloc_pages_node(node, flags, order);
+	shadow = alloc_pages_node(node, flags | __GFP_NOTRACK, order);
 	if (!shadow) {
 		if (printk_ratelimit())
 			printk(KERN_ERR "kmemcheck: failed to allocate "
@@ -33,23 +33,17 @@ void kmemcheck_alloc_shadow(struct kmem_cache *s, gfp_t flags, int node,
 	 * the memory accesses.
 	 */
 	kmemcheck_hide_pages(page, pages);
-
-	/*
-	 * Objects from caches that have a constructor don't get
-	 * cleared when they're allocated, so we need to do it here.
-	 */
-	if (s->ctor)
-		kmemcheck_mark_uninitialized_pages(page, pages);
-	else
-		kmemcheck_mark_unallocated_pages(page, pages);
 }
 
-void kmemcheck_free_shadow(struct kmem_cache *s, struct page *page, int order)
+void kmemcheck_free_shadow(struct page *page, int order)
 {
 	struct page *shadow;
 	int pages;
 	int i;
 
+	if (!kmemcheck_page_is_tracked(page))
+		return;
+
 	pages = 1 << order;
 
 	kmemcheck_show_pages(page, pages);
@@ -101,3 +95,28 @@ void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size)
 	if (!s->ctor && !(s->flags & SLAB_DESTROY_BY_RCU))
 		kmemcheck_mark_freed(object, size);
 }
+
+void kmemcheck_pagealloc_alloc(struct page *page, unsigned int order,
+			       gfp_t gfpflags)
+{
+	int pages;
+
+	if (gfpflags & (__GFP_HIGHMEM | __GFP_NOTRACK))
+		return;
+
+	pages = 1 << order;
+
+	/*
+	 * NOTE: We choose to track GFP_ZERO pages too; in fact, they
+	 * can become uninitialized by copying uninitialized memory
+	 * into them.
+	 */
+
+	/* XXX: Can use zone->node for node? */
+	kmemcheck_alloc_shadow(page, order, gfpflags, -1);
+
+	if (gfpflags & __GFP_ZERO)
+		kmemcheck_mark_initialized_pages(page, pages);
+	else
+		kmemcheck_mark_uninitialized_pages(page, pages);
+}