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>
diff --git a/mm/kmemcheck.c b/mm/kmemcheck.c
index eaa41b8..fd814fd 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 @@
* 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 @@
* 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 @@
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);
+}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 17d5f53..0727896 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -23,6 +23,7 @@
#include <linux/bootmem.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
+#include <linux/kmemcheck.h>
#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/pagevec.h>
@@ -546,6 +547,8 @@
int i;
int bad = 0;
+ kmemcheck_free_shadow(page, order);
+
for (i = 0 ; i < (1 << order) ; ++i)
bad += free_pages_check(page + i);
if (bad)
@@ -994,6 +997,8 @@
struct per_cpu_pages *pcp;
unsigned long flags;
+ kmemcheck_free_shadow(page, 0);
+
if (PageAnon(page))
page->mapping = NULL;
if (free_pages_check(page))
@@ -1047,6 +1052,16 @@
VM_BUG_ON(PageCompound(page));
VM_BUG_ON(!page_count(page));
+
+#ifdef CONFIG_KMEMCHECK
+ /*
+ * Split shadow pages too, because free(page[0]) would
+ * otherwise free the whole shadow.
+ */
+ if (kmemcheck_page_is_tracked(page))
+ split_page(virt_to_page(page[0].shadow), order);
+#endif
+
for (i = 1; i < (1 << order); i++)
set_page_refcounted(page + i);
}
@@ -1667,7 +1682,10 @@
dump_stack();
show_mem();
}
+ return page;
got_pg:
+ if (kmemcheck_enabled)
+ kmemcheck_pagealloc_alloc(page, order, gfp_mask);
return page;
}
EXPORT_SYMBOL(__alloc_pages_internal);
diff --git a/mm/slab.c b/mm/slab.c
index 95b6c5e..6a1ad0b 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1612,7 +1612,7 @@
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
flags |= __GFP_RECLAIMABLE;
- page = alloc_pages_node(nodeid, flags, cachep->gfporder);
+ page = alloc_pages_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
if (!page)
return NULL;
@@ -1626,8 +1626,14 @@
for (i = 0; i < nr_pages; i++)
__SetPageSlab(page + i);
- if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK))
- kmemcheck_alloc_shadow(cachep, flags, nodeid, page, cachep->gfporder);
+ if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
+ kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
+
+ if (cachep->ctor)
+ kmemcheck_mark_uninitialized_pages(page, nr_pages);
+ else
+ kmemcheck_mark_unallocated_pages(page, nr_pages);
+ }
return page_address(page);
}
@@ -1641,8 +1647,7 @@
struct page *page = virt_to_page(addr);
const unsigned long nr_freed = i;
- if (kmemcheck_page_is_tracked(page))
- kmemcheck_free_shadow(cachep, page, cachep->gfporder);
+ kmemcheck_free_shadow(page, cachep->gfporder);
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
sub_zone_page_state(page_zone(page),
diff --git a/mm/slub.c b/mm/slub.c
index 1cebaa7..898fb50 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1066,6 +1066,8 @@
{
int order = oo_order(oo);
+ flags |= __GFP_NOTRACK;
+
if (node == -1)
return alloc_pages(flags, order);
else
@@ -1097,7 +1099,18 @@
if (kmemcheck_enabled
&& !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS)))
{
- kmemcheck_alloc_shadow(s, flags, node, page, compound_order(page));
+ int pages = 1 << oo_order(oo);
+
+ kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
+
+ /*
+ * 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);
}
page->objects = oo_objects(oo);
@@ -1173,8 +1186,7 @@
__ClearPageSlubDebug(page);
}
- if (kmemcheck_page_is_tracked(page))
- kmemcheck_free_shadow(s, page, compound_order(page));
+ kmemcheck_free_shadow(page, compound_order(page));
mod_zone_page_state(page_zone(page),
(s->flags & SLAB_RECLAIM_ACCOUNT) ?
@@ -2734,9 +2746,10 @@
static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
{
- struct page *page = alloc_pages_node(node, flags | __GFP_COMP,
- get_order(size));
+ struct page *page;
+ flags |= __GFP_COMP | __GFP_NOTRACK;
+ page = alloc_pages_node(node, flags, get_order(size));
if (page)
return page_address(page);
else