Blame view
mm/page_poison.c
3.13 KB
b24413180 License cleanup: ... |
1 |
// SPDX-License-Identifier: GPL-2.0 |
6a11f75b6 generic debug pag... |
2 |
#include <linux/kernel.h> |
8c5fb8ead mm/debug-pageallo... |
3 |
#include <linux/string.h> |
6a11f75b6 generic debug pag... |
4 |
#include <linux/mm.h> |
64212ec56 debug-pagealloc: ... |
5 |
#include <linux/highmem.h> |
e30825f18 mm/debug-pageallo... |
6 |
#include <linux/page_ext.h> |
6a11f75b6 generic debug pag... |
7 |
#include <linux/poison.h> |
77311139f mm/debug-pageallo... |
8 |
#include <linux/ratelimit.h> |
4117992df page_poison: play... |
9 |
#include <linux/kasan.h> |
6a11f75b6 generic debug pag... |
10 |
|
11c9c7eda mm/page_poison.c:... |
11 |
static DEFINE_STATIC_KEY_FALSE_RO(want_page_poisoning); |
e30825f18 mm/debug-pageallo... |
12 |
|
14298d366 mm/page_poison.c:... |
13 |
static int __init early_page_poison_param(char *buf) |
e30825f18 mm/debug-pageallo... |
14 |
{ |
11c9c7eda mm/page_poison.c:... |
15 16 17 18 19 20 21 22 23 24 25 26 27 |
int ret; bool tmp; ret = strtobool(buf, &tmp); if (ret) return ret; if (tmp) static_branch_enable(&want_page_poisoning); else static_branch_disable(&want_page_poisoning); return 0; |
8823b1dbc mm/page_poison.c:... |
28 29 |
} early_param("page_poison", early_page_poison_param); |
d95f58f4a mm/page_poison: e... |
30 31 32 33 34 |
/** * page_poisoning_enabled - check if page poisoning is enabled * * Return true if page poisoning is enabled, or false if not. */ |
8823b1dbc mm/page_poison.c:... |
35 36 |
bool page_poisoning_enabled(void) { |
8823b1dbc mm/page_poison.c:... |
37 |
/* |
bd33ef368 mm: enable page p... |
38 |
* Assumes that debug_pagealloc_enabled is set before |
c6ffc5ca8 memblock: rename ... |
39 |
* memblock_free_all. |
bd33ef368 mm: enable page p... |
40 41 |
* Page poisoning is debug page alloc for some arches. If * either of those options are enabled, enable poisoning. |
8823b1dbc mm/page_poison.c:... |
42 |
*/ |
11c9c7eda mm/page_poison.c:... |
43 |
return (static_branch_unlikely(&want_page_poisoning) || |
bd33ef368 mm: enable page p... |
44 45 |
(!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) && debug_pagealloc_enabled())); |
6a11f75b6 generic debug pag... |
46 |
} |
d95f58f4a mm/page_poison: e... |
47 |
EXPORT_SYMBOL_GPL(page_poisoning_enabled); |
6a11f75b6 generic debug pag... |
48 |
|
6a11f75b6 generic debug pag... |
49 50 |
static void poison_page(struct page *page) { |
64212ec56 debug-pagealloc: ... |
51 |
void *addr = kmap_atomic(page); |
6a11f75b6 generic debug pag... |
52 |
|
4117992df page_poison: play... |
53 54 |
/* KASAN still think the page is in-use, so skip it. */ kasan_disable_current(); |
6a11f75b6 generic debug pag... |
55 |
memset(addr, PAGE_POISON, PAGE_SIZE); |
4117992df page_poison: play... |
56 |
kasan_enable_current(); |
64212ec56 debug-pagealloc: ... |
57 |
kunmap_atomic(addr); |
6a11f75b6 generic debug pag... |
58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 |
} static void poison_pages(struct page *page, int n) { int i; for (i = 0; i < n; i++) poison_page(page + i); } static bool single_bit_flip(unsigned char a, unsigned char b) { unsigned char error = a ^ b; return error && !(error & (error - 1)); } static void check_poison_mem(unsigned char *mem, size_t bytes) { |
77311139f mm/debug-pageallo... |
77 |
static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10); |
6a11f75b6 generic debug pag... |
78 79 |
unsigned char *start; unsigned char *end; |
8823b1dbc mm/page_poison.c:... |
80 81 |
if (IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY)) return; |
8c5fb8ead mm/debug-pageallo... |
82 83 |
start = memchr_inv(mem, PAGE_POISON, bytes); if (!start) |
6a11f75b6 generic debug pag... |
84 85 86 87 88 89 |
return; for (end = mem + bytes - 1; end > start; end--) { if (*end != PAGE_POISON) break; } |
77311139f mm/debug-pageallo... |
90 |
if (!__ratelimit(&ratelimit)) |
6a11f75b6 generic debug pag... |
91 92 |
return; else if (start == end && single_bit_flip(*start, PAGE_POISON)) |
8823b1dbc mm/page_poison.c:... |
93 94 |
pr_err("pagealloc: single bit error "); |
6a11f75b6 generic debug pag... |
95 |
else |
8823b1dbc mm/page_poison.c:... |
96 97 |
pr_err("pagealloc: memory corruption "); |
6a11f75b6 generic debug pag... |
98 99 100 101 102 |
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start, end - start + 1, 1); dump_stack(); } |
6a11f75b6 generic debug pag... |
103 104 |
static void unpoison_page(struct page *page) { |
64212ec56 debug-pagealloc: ... |
105 |
void *addr; |
64212ec56 debug-pagealloc: ... |
106 |
addr = kmap_atomic(page); |
bd33ef368 mm: enable page p... |
107 108 109 |
/* * Page poisoning when enabled poisons each and every page * that is freed to buddy. Thus no extra check is done to |
dbf7684e2 mm/page_poison.c:... |
110 |
* see if a page was poisoned. |
bd33ef368 mm: enable page p... |
111 |
*/ |
64212ec56 debug-pagealloc: ... |
112 |
check_poison_mem(addr, PAGE_SIZE); |
64212ec56 debug-pagealloc: ... |
113 |
kunmap_atomic(addr); |
6a11f75b6 generic debug pag... |
114 115 116 117 118 119 120 121 122 |
} static void unpoison_pages(struct page *page, int n) { int i; for (i = 0; i < n; i++) unpoison_page(page + i); } |
8823b1dbc mm/page_poison.c:... |
123 |
void kernel_poison_pages(struct page *page, int numpages, int enable) |
6a11f75b6 generic debug pag... |
124 |
{ |
8823b1dbc mm/page_poison.c:... |
125 |
if (!page_poisoning_enabled()) |
e30825f18 mm/debug-pageallo... |
126 |
return; |
6a11f75b6 generic debug pag... |
127 128 129 130 131 |
if (enable) unpoison_pages(page, numpages); else poison_pages(page, numpages); } |
8823b1dbc mm/page_poison.c:... |
132 133 134 135 136 137 138 |
#ifndef CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { /* This function does nothing, all work is done via poison pages */ } #endif |