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);
+}