Root/
| 1 | #include <linux/kernel.h> |
| 2 | #include <linux/string.h> |
| 3 | #include <linux/mm.h> |
| 4 | #include <linux/highmem.h> |
| 5 | #include <linux/page-debug-flags.h> |
| 6 | #include <linux/poison.h> |
| 7 | #include <linux/ratelimit.h> |
| 8 | |
| 9 | static inline void set_page_poison(struct page *page) |
| 10 | { |
| 11 | __set_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags); |
| 12 | } |
| 13 | |
| 14 | static inline void clear_page_poison(struct page *page) |
| 15 | { |
| 16 | __clear_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags); |
| 17 | } |
| 18 | |
| 19 | static inline bool page_poison(struct page *page) |
| 20 | { |
| 21 | return test_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags); |
| 22 | } |
| 23 | |
| 24 | static void poison_page(struct page *page) |
| 25 | { |
| 26 | void *addr = kmap_atomic(page); |
| 27 | |
| 28 | set_page_poison(page); |
| 29 | memset(addr, PAGE_POISON, PAGE_SIZE); |
| 30 | kunmap_atomic(addr); |
| 31 | } |
| 32 | |
| 33 | static void poison_pages(struct page *page, int n) |
| 34 | { |
| 35 | int i; |
| 36 | |
| 37 | for (i = 0; i < n; i++) |
| 38 | poison_page(page + i); |
| 39 | } |
| 40 | |
| 41 | static bool single_bit_flip(unsigned char a, unsigned char b) |
| 42 | { |
| 43 | unsigned char error = a ^ b; |
| 44 | |
| 45 | return error && !(error & (error - 1)); |
| 46 | } |
| 47 | |
| 48 | static void check_poison_mem(unsigned char *mem, size_t bytes) |
| 49 | { |
| 50 | static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10); |
| 51 | unsigned char *start; |
| 52 | unsigned char *end; |
| 53 | |
| 54 | start = memchr_inv(mem, PAGE_POISON, bytes); |
| 55 | if (!start) |
| 56 | return; |
| 57 | |
| 58 | for (end = mem + bytes - 1; end > start; end--) { |
| 59 | if (*end != PAGE_POISON) |
| 60 | break; |
| 61 | } |
| 62 | |
| 63 | if (!__ratelimit(&ratelimit)) |
| 64 | return; |
| 65 | else if (start == end && single_bit_flip(*start, PAGE_POISON)) |
| 66 | printk(KERN_ERR "pagealloc: single bit error\n"); |
| 67 | else |
| 68 | printk(KERN_ERR "pagealloc: memory corruption\n"); |
| 69 | |
| 70 | print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start, |
| 71 | end - start + 1, 1); |
| 72 | dump_stack(); |
| 73 | } |
| 74 | |
| 75 | static void unpoison_page(struct page *page) |
| 76 | { |
| 77 | void *addr; |
| 78 | |
| 79 | if (!page_poison(page)) |
| 80 | return; |
| 81 | |
| 82 | addr = kmap_atomic(page); |
| 83 | check_poison_mem(addr, PAGE_SIZE); |
| 84 | clear_page_poison(page); |
| 85 | kunmap_atomic(addr); |
| 86 | } |
| 87 | |
| 88 | static void unpoison_pages(struct page *page, int n) |
| 89 | { |
| 90 | int i; |
| 91 | |
| 92 | for (i = 0; i < n; i++) |
| 93 | unpoison_page(page + i); |
| 94 | } |
| 95 | |
| 96 | void kernel_map_pages(struct page *page, int numpages, int enable) |
| 97 | { |
| 98 | if (enable) |
| 99 | unpoison_pages(page, numpages); |
| 100 | else |
| 101 | poison_pages(page, numpages); |
| 102 | } |
| 103 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9
