Commit b1eeab67 authored by Vegard Nossum's avatar Vegard Nossum
Browse files

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: default avatarPekka Enberg <penberg@cs.helsinki.fi>

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

[rebased for mainline inclusion]
Signed-off-by: default avatarVegard Nossum <vegard.nossum@gmail.com>
parent 9b5cab31
......@@ -154,9 +154,9 @@ struct thread_info {
/* thread information allocation */
#ifdef CONFIG_DEBUG_STACK_USAGE
#define THREAD_FLAGS (GFP_KERNEL | __GFP_ZERO)
#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
#else
#define THREAD_FLAGS GFP_KERNEL
#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK)
#endif
#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
......
......@@ -116,6 +116,14 @@ void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n)
kmemcheck_mark_uninitialized(page_address(&p[i]), PAGE_SIZE);
}
void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n)
{
unsigned int i;
for (i = 0; i < n; ++i)
kmemcheck_mark_initialized(page_address(&p[i]), PAGE_SIZE);
}
enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size)
{
uint8_t *x;
......
......@@ -51,7 +51,12 @@ struct vm_area_struct;
#define __GFP_THISNODE ((__force gfp_t)0x40000u)/* No fallback, no policies */
#define __GFP_RECLAIMABLE ((__force gfp_t)0x80000u) /* Page is reclaimable */
#define __GFP_MOVABLE ((__force gfp_t)0x100000u) /* Page is movable */
#ifdef CONFIG_KMEMCHECK
#define __GFP_NOTRACK ((__force gfp_t)0x200000u) /* Don't track with kmemcheck */
#else
#define __GFP_NOTRACK ((__force gfp_t)0)
#endif
/*
* This may seem redundant, but it's a way of annotating false positives vs.
......
......@@ -8,13 +8,15 @@
extern int kmemcheck_enabled;
/* The slab-related functions. */
void kmemcheck_alloc_shadow(struct kmem_cache *s, gfp_t flags, int node,
struct page *page, int order);
void kmemcheck_free_shadow(struct kmem_cache *s, struct page *page, int order);
void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node);
void kmemcheck_free_shadow(struct page *page, int order);
void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
size_t size);
void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size);
void kmemcheck_pagealloc_alloc(struct page *p, unsigned int order,
gfp_t gfpflags);
void kmemcheck_show_pages(struct page *p, unsigned int n);
void kmemcheck_hide_pages(struct page *p, unsigned int n);
......@@ -27,6 +29,7 @@ void kmemcheck_mark_freed(void *address, unsigned int n);
void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n);
void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n);
void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n);
int kmemcheck_show_addr(unsigned long address);
int kmemcheck_hide_addr(unsigned long address);
......@@ -34,13 +37,12 @@ int kmemcheck_hide_addr(unsigned long address);
#define kmemcheck_enabled 0
static inline void
kmemcheck_alloc_shadow(struct kmem_cache *s, gfp_t flags, int node,
struct page *page, int order)
kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
{
}
static inline void
kmemcheck_free_shadow(struct kmem_cache *s, struct page *page, int order)
kmemcheck_free_shadow(struct page *page, int order)
{
}
......@@ -55,6 +57,11 @@ static inline void kmemcheck_slab_free(struct kmem_cache *s, void *object,
{
}
static inline void kmemcheck_pagealloc_alloc(struct page *p,
unsigned int order, gfp_t gfpflags)
{
}
static inline bool kmemcheck_page_is_tracked(struct page *p)
{
return false;
......@@ -75,6 +82,22 @@ static inline void kmemcheck_mark_initialized(void *address, unsigned int n)
static inline void kmemcheck_mark_freed(void *address, unsigned int n)
{
}
static inline void kmemcheck_mark_unallocated_pages(struct page *p,
unsigned int n)
{
}
static inline void kmemcheck_mark_uninitialized_pages(struct page *p,
unsigned int n)
{
}
static inline void kmemcheck_mark_initialized_pages(struct page *p,
unsigned int n)
{
}
#endif /* CONFIG_KMEMCHECK */
#endif /* LINUX_KMEMCHECK_H */
#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);
}
......@@ -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 @@ static void __free_pages_ok(struct page *page, unsigned int order)
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 @@ static void free_hot_cold_page(struct page *page, int cold)
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 @@ void split_page(struct page *page, unsigned int order)
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 @@ nopage:
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);
......
......@@ -1612,7 +1612,7 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
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 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
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 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr)
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),
......
......@@ -1066,6 +1066,8 @@ static inline struct page *alloc_slab_page(gfp_t flags, int node,
{
int order = oo_order(oo);
flags |= __GFP_NOTRACK;
if (node == -1)
return alloc_pages(flags, order);
else
......@@ -1097,7 +1099,18 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
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 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
__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 @@ EXPORT_SYMBOL(__kmalloc);
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
......
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