blob: 5bf191756a4a07b04ffe1dd792f475e1e0af0492
1 | #include <linux/gfp.h> |
2 | #include <linux/mm_types.h> |
3 | #include <linux/mm.h> |
4 | #include <linux/slab.h> |
5 | #include "slab.h" |
6 | #include <linux/kmemcheck.h> |
7 | |
8 | void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node) |
9 | { |
10 | struct page *shadow; |
11 | int pages; |
12 | int i; |
13 | |
14 | pages = 1 << order; |
15 | |
16 | /* |
17 | * With kmemcheck enabled, we need to allocate a memory area for the |
18 | * shadow bits as well. |
19 | */ |
20 | shadow = alloc_pages_node(node, flags | __GFP_NOTRACK, order); |
21 | if (!shadow) { |
22 | if (printk_ratelimit()) |
23 | pr_err("kmemcheck: failed to allocate shadow bitmap\n"); |
24 | return; |
25 | } |
26 | |
27 | for(i = 0; i < pages; ++i) |
28 | page[i].shadow = page_address(&shadow[i]); |
29 | |
30 | /* |
31 | * Mark it as non-present for the MMU so that our accesses to |
32 | * this memory will trigger a page fault and let us analyze |
33 | * the memory accesses. |
34 | */ |
35 | kmemcheck_hide_pages(page, pages); |
36 | } |
37 | |
38 | void kmemcheck_free_shadow(struct page *page, int order) |
39 | { |
40 | struct page *shadow; |
41 | int pages; |
42 | int i; |
43 | |
44 | if (!kmemcheck_page_is_tracked(page)) |
45 | return; |
46 | |
47 | pages = 1 << order; |
48 | |
49 | kmemcheck_show_pages(page, pages); |
50 | |
51 | shadow = virt_to_page(page[0].shadow); |
52 | |
53 | for(i = 0; i < pages; ++i) |
54 | page[i].shadow = NULL; |
55 | |
56 | __free_pages(shadow, order); |
57 | } |
58 | |
59 | void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object, |
60 | size_t size) |
61 | { |
62 | if (unlikely(!object)) /* Skip object if allocation failed */ |
63 | return; |
64 | |
65 | /* |
66 | * Has already been memset(), which initializes the shadow for us |
67 | * as well. |
68 | */ |
69 | if (gfpflags & __GFP_ZERO) |
70 | return; |
71 | |
72 | /* No need to initialize the shadow of a non-tracked slab. */ |
73 | if (s->flags & SLAB_NOTRACK) |
74 | return; |
75 | |
76 | if (!kmemcheck_enabled || gfpflags & __GFP_NOTRACK) { |
77 | /* |
78 | * Allow notracked objects to be allocated from |
79 | * tracked caches. Note however that these objects |
80 | * will still get page faults on access, they just |
81 | * won't ever be flagged as uninitialized. If page |
82 | * faults are not acceptable, the slab cache itself |
83 | * should be marked NOTRACK. |
84 | */ |
85 | kmemcheck_mark_initialized(object, size); |
86 | } else if (!s->ctor) { |
87 | /* |
88 | * New objects should be marked uninitialized before |
89 | * they're returned to the called. |
90 | */ |
91 | kmemcheck_mark_uninitialized(object, size); |
92 | } |
93 | } |
94 | |
95 | void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size) |
96 | { |
97 | /* TODO: RCU freeing is unsupported for now; hide false positives. */ |
98 | if (!s->ctor && !(s->flags & SLAB_DESTROY_BY_RCU)) |
99 | kmemcheck_mark_freed(object, size); |
100 | } |
101 | |
102 | void kmemcheck_pagealloc_alloc(struct page *page, unsigned int order, |
103 | gfp_t gfpflags) |
104 | { |
105 | int pages; |
106 | |
107 | if (gfpflags & (__GFP_HIGHMEM | __GFP_NOTRACK)) |
108 | return; |
109 | |
110 | pages = 1 << order; |
111 | |
112 | /* |
113 | * NOTE: We choose to track GFP_ZERO pages too; in fact, they |
114 | * can become uninitialized by copying uninitialized memory |
115 | * into them. |
116 | */ |
117 | |
118 | /* XXX: Can use zone->node for node? */ |
119 | kmemcheck_alloc_shadow(page, order, gfpflags, -1); |
120 | |
121 | if (gfpflags & __GFP_ZERO) |
122 | kmemcheck_mark_initialized_pages(page, pages); |
123 | else |
124 | kmemcheck_mark_uninitialized_pages(page, pages); |
125 | } |
126 |