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