aboutsummaryrefslogtreecommitdiffstats
path: root/tools/testing/selftests/vm/mlock-random-test.c
blob: 83de4f58d2629cda7964520188bf8e4138be8ad1 (plain) (blame)
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
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
/*
 * It tests the mlock/mlock2() when they are invoked
 * on randomly memory region.
 */
#include <unistd.h>
#include <sys/resource.h>
#include <sys/capability.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <time.h>
#include "mlock2.h"

#define CHUNK_UNIT (128 * 1024)
#define MLOCK_RLIMIT_SIZE (CHUNK_UNIT * 2)
#define MLOCK_WITHIN_LIMIT_SIZE CHUNK_UNIT
#define MLOCK_OUTOF_LIMIT_SIZE (CHUNK_UNIT * 3)

#define TEST_LOOP 100
#define PAGE_ALIGN(size, ps) (((size) + ((ps) - 1)) & ~((ps) - 1))

int set_cap_limits(rlim_t max)
{
	struct rlimit new;
	cap_t cap = cap_init();

	new.rlim_cur = max;
	new.rlim_max = max;
	if (setrlimit(RLIMIT_MEMLOCK, &new)) {
		perror("setrlimit() returns error\n");
		return -1;
	}

	/* drop capabilities including CAP_IPC_LOCK */
	if (cap_set_proc(cap)) {
		perror("cap_set_proc() returns error\n");
		return -2;
	}

	return 0;
}

int get_proc_locked_vm_size(void)
{
	FILE *f;
	int ret = -1;
	char line[1024] = {0};
	unsigned long lock_size = 0;

	f = fopen("/proc/self/status", "r");
	if (!f) {
		perror("fopen");
		return -1;
	}

	while (fgets(line, 1024, f)) {
		if (strstr(line, "VmLck")) {
			ret = sscanf(line, "VmLck:\t%8lu kB", &lock_size);
			if (ret <= 0) {
				printf("sscanf() on VmLck error: %s: %d\n",
						line, ret);
				fclose(f);
				return -1;
			}
			fclose(f);
			return (int)(lock_size << 10);
		}
	}

	perror("cann't parse VmLck in /proc/self/status\n");
	fclose(f);
	return -1;
}

/*
 * Get the MMUPageSize of the memory region including input
 * address from proc file.
 *
 * return value: on error case, 0 will be returned.
 * Otherwise the page size(in bytes) is returned.
 */
int get_proc_page_size(unsigned long addr)
{
	FILE *smaps;
	char *line;
	unsigned long mmupage_size = 0;
	size_t size;

	smaps = seek_to_smaps_entry(addr);
	if (!smaps) {
		printf("Unable to parse /proc/self/smaps\n");
		return 0;
	}

	while (getline(&line, &size, smaps) > 0) {
		if (!strstr(line, "MMUPageSize")) {
			free(line);
			line = NULL;
			size = 0;
			continue;
		}

		/* found the MMUPageSize of this section */
		if (sscanf(line, "MMUPageSize:    %8lu kB",
					&mmupage_size) < 1) {
			printf("Unable to parse smaps entry for Size:%s\n",
					line);
			break;
		}

	}
	free(line);
	if (smaps)
		fclose(smaps);
	return mmupage_size << 10;
}

/*
 * Test mlock/mlock2() on provided memory chunk.
 * It expects the mlock/mlock2() to be successful (within rlimit)
 *
 * With allocated memory chunk [p, p + alloc_size), this
 * test will choose start/len randomly to perform mlock/mlock2
 * [start, start +  len] memory range. The range is within range
 * of the allocated chunk.
 *
 * The memory region size alloc_size is within the rlimit.
 * So we always expect a success of mlock/mlock2.
 *
 * VmLck is assumed to be 0 before this test.
 *
 *    return value: 0 - success
 *    else: failure
 */
int test_mlock_within_limit(char *p, int alloc_size)
{
	int i;
	int ret = 0;
	int locked_vm_size = 0;
	struct rlimit cur;
	int page_size = 0;

	getrlimit(RLIMIT_MEMLOCK, &cur);
	if (cur.rlim_cur < alloc_size) {
		printf("alloc_size[%d] < %u rlimit,lead to mlock failure\n",
				alloc_size, (unsigned int)cur.rlim_cur);
		return -1;
	}

	srand(time(NULL));
	for (i = 0; i < TEST_LOOP; i++) {
		/*
		 * - choose mlock/mlock2 randomly
		 * - choose lock_size randomly but lock_size < alloc_size
		 * - choose start_offset randomly but p+start_offset+lock_size
		 *   < p+alloc_size
		 */
		int is_mlock = !!(rand() % 2);
		int lock_size = rand() % alloc_size;
		int start_offset = rand() % (alloc_size - lock_size);

		if (is_mlock)
			ret = mlock(p + start_offset, lock_size);
		else
			ret = mlock2_(p + start_offset, lock_size,
				       MLOCK_ONFAULT);

		if (ret) {
			printf("%s() failure at |%p(%d)| mlock:|%p(%d)|\n",
					is_mlock ? "mlock" : "mlock2",
					p, alloc_size,
					p + start_offset, lock_size);
			return ret;
		}
	}

	/*
	 * Check VmLck left by the tests.
	 */
	locked_vm_size = get_proc_locked_vm_size();
	page_size = get_proc_page_size((unsigned long)p);
	if (page_size == 0) {
		printf("cannot get proc MMUPageSize\n");
		return -1;
	}

	if (locked_vm_size > PAGE_ALIGN(alloc_size, page_size) + page_size) {
		printf("test_mlock_within_limit() left VmLck:%d on %d chunk\n",
				locked_vm_size, alloc_size);
		return -1;
	}

	return 0;
}


/*
 * We expect the mlock/mlock2() to be fail (outof limitation)
 *
 * With allocated memory chunk [p, p + alloc_size), this
 * test will randomly choose start/len and perform mlock/mlock2
 * on [start, start+len] range.
 *
 * The memory region size alloc_size is above the rlimit.
 * And the len to be locked is higher than rlimit.
 * So we always expect a failure of mlock/mlock2.
 * No locked page number should be increased as a side effect.
 *
 *    return value: 0 - success
 *    else: failure
 */
int test_mlock_outof_limit(char *p, int alloc_size)
{
	int i;
	int ret = 0;
	int locked_vm_size = 0, old_locked_vm_size = 0;
	struct rlimit cur;

	getrlimit(RLIMIT_MEMLOCK, &cur);
	if (cur.rlim_cur >= alloc_size) {
		printf("alloc_size[%d] >%u rlimit, violates test condition\n",
				alloc_size, (unsigned int)cur.rlim_cur);
		return -1;
	}

	old_locked_vm_size = get_proc_locked_vm_size();
	srand(time(NULL));
	for (i = 0; i < TEST_LOOP; i++) {
		int is_mlock = !!(rand() % 2);
		int lock_size = (rand() % (alloc_size - cur.rlim_cur))
			+ cur.rlim_cur;
		int start_offset = rand() % (alloc_size - lock_size);

		if (is_mlock)
			ret = mlock(p + start_offset, lock_size);
		else
			ret = mlock2_(p + start_offset, lock_size,
					MLOCK_ONFAULT);
		if (ret == 0) {
			printf("%s() succeeds? on %p(%d) mlock%p(%d)\n",
					is_mlock ? "mlock" : "mlock2",
					p, alloc_size,
					p + start_offset, lock_size);
			return -1;
		}
	}

	locked_vm_size = get_proc_locked_vm_size();
	if (locked_vm_size != old_locked_vm_size) {
		printf("tests leads to new mlocked page: old[%d], new[%d]\n",
				old_locked_vm_size,
				locked_vm_size);
		return -1;
	}

	return 0;
}

int main(int argc, char **argv)
{
	char *p = NULL;
	int ret = 0;

	if (set_cap_limits(MLOCK_RLIMIT_SIZE))
		return -1;

	p = malloc(MLOCK_WITHIN_LIMIT_SIZE);
	if (p == NULL) {
		perror("malloc() failure\n");
		return -1;
	}
	ret = test_mlock_within_limit(p, MLOCK_WITHIN_LIMIT_SIZE);
	if (ret)
		return ret;
	munlock(p, MLOCK_WITHIN_LIMIT_SIZE);
	free(p);


	p = malloc(MLOCK_OUTOF_LIMIT_SIZE);
	if (p == NULL) {
		perror("malloc() failure\n");
		return -1;
	}
	ret = test_mlock_outof_limit(p, MLOCK_OUTOF_LIMIT_SIZE);
	if (ret)
		return ret;
	munlock(p, MLOCK_OUTOF_LIMIT_SIZE);
	free(p);

	return 0;
}