1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
|
#include <linux/gfp.h>
#include <linux/mm_types.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include "slab.h"
#include <linux/kmemcheck.h>
void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
{
struct page *shadow;
int pages;
int i;
pages = 1 << order;
/*
* With kmemcheck enabled, we need to allocate a memory area for the
* shadow bits as well.
*/
shadow = alloc_pages_node(node, flags | __GFP_NOTRACK, order);
if (!shadow) {
if (printk_ratelimit())
pr_err("kmemcheck: failed to allocate shadow bitmap\n");
return;
}
for(i = 0; i < pages; ++i)
page[i].shadow = page_address(&shadow[i]);
/*
* Mark it as non-present for the MMU so that our accesses to
* this memory will trigger a page fault and let us analyze
* the memory accesses.
*/
kmemcheck_hide_pages(page, pages);
}
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);
shadow = virt_to_page(page[0].shadow);
for(i = 0; i < pages; ++i)
page[i].shadow = NULL;
__free_pages(shadow, order);
}
void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
size_t size)
{
if (unlikely(!object)) /* Skip object if allocation failed */
return;
/*
* Has already been memset(), which initializes the shadow for us
* as well.
*/
if (gfpflags & __GFP_ZERO)
return;
/* No need to initialize the shadow of a non-tracked slab. */
if (s->flags & SLAB_NOTRACK)
return;
if (!kmemcheck_enabled || gfpflags & __GFP_NOTRACK) {
/*
* Allow notracked objects to be allocated from
* tracked caches. Note however that these objects
* will still get page faults on access, they just
* won't ever be flagged as uninitialized. If page
* faults are not acceptable, the slab cache itself
* should be marked NOTRACK.
*/
kmemcheck_mark_initialized(object, size);
} else if (!s->ctor) {
/*
* New objects should be marked uninitialized before
* they're returned to the called.
*/
kmemcheck_mark_uninitialized(object, size);
}
}
void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size)
{
/* TODO: RCU freeing is unsupported for now; hide false positives. */
if (!s->ctor && !(s->flags & SLAB_TYPESAFE_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);
}
|
