1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright Red Hat
4 * Author: Filippo Storniolo <[email protected]>
5 */
6
7 /*\
8 * [Description]
9 *
10 * Verify mlock() causes pre-faulting of PTEs and prevent memory to be swapped out.
11 *
12 * Find the new mapping in /proc/$pid/smaps and check Rss and Locked fields after
13 * mlock syscall:
14 * Rss and Locked size should be equal to the size of the memory allocation
15 */
16
17 #include "tst_test.h"
18 #include "tst_safe_stdio.h"
19
20 #define MMAPLEN (1UL<<20)
21 #define LINELEN 256
22
get_proc_smaps_info(unsigned long desired_mapping_address,unsigned long * Rss,unsigned long * Locked)23 static void get_proc_smaps_info(unsigned long desired_mapping_address, unsigned long *Rss, unsigned long *Locked)
24 {
25 bool mapping_found = false;
26 bool Locked_found = false;
27 bool Rss_found = false;
28 char buffer[LINELEN];
29 FILE *fp;
30 int ret;
31
32 fp = SAFE_FOPEN("/proc/self/smaps", "r");
33
34 while (fgets(buffer, LINELEN, fp) != NULL) {
35 unsigned long mapping_address;
36
37 ret = sscanf(buffer, "%lx[^-]", &mapping_address);
38 if ((ret == 1) && (mapping_address == desired_mapping_address)) {
39 mapping_found = true;
40 break;
41 }
42 }
43
44 if (!mapping_found) {
45 SAFE_FCLOSE(fp);
46 tst_brk(TBROK, "Mapping %lx not found in /proc/self/smaps", desired_mapping_address);
47 return;
48 }
49
50 while (fgets(buffer, LINELEN, fp) != NULL) {
51 unsigned long possible_starting_mapping;
52 unsigned long possible_ending_mapping;
53
54 ret = sscanf(buffer, "%lx-%lx", &possible_starting_mapping, &possible_ending_mapping);
55 if (ret == 2)
56 break;
57
58 if (strncmp(buffer, "Rss", strlen("Rss")) == 0) {
59 ret = sscanf(buffer, "%*[^:]:%lu kB", Rss);
60 if (ret != 1) {
61 SAFE_FCLOSE(fp);
62 tst_brk(TBROK, "failure occurred while reading field Rss");
63 return;
64 }
65
66 Rss_found = true;
67 }
68
69 if (strncmp(buffer, "Locked", strlen("Locked")) == 0) {
70 ret = sscanf(buffer, "%*[^:]:%lu kB", Locked);
71 if (ret != 1) {
72 SAFE_FCLOSE(fp);
73 tst_brk(TBROK, "failure occurred while reading field Locked");
74 return;
75 }
76
77 Locked_found = true;
78 }
79
80 if (Rss_found && Locked_found) {
81 SAFE_FCLOSE(fp);
82 return;
83 }
84 }
85
86 SAFE_FCLOSE(fp);
87 tst_brk(TBROK, "cannot find both Rss and Locked in mapping %lx", desired_mapping_address);
88 }
89
verify_mlock(void)90 static void verify_mlock(void)
91 {
92 unsigned long Locked;
93 unsigned long Rss;
94 char *buf;
95
96 buf = SAFE_MMAP(NULL, MMAPLEN, PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
97 SAFE_MLOCK(buf, MMAPLEN);
98
99 get_proc_smaps_info((unsigned long)buf, &Rss, &Locked);
100
101 // Convertion from KiB to B
102 Rss *= 1024;
103 Locked *= 1024;
104
105 TST_EXP_EQ_LU(Rss, MMAPLEN);
106 TST_EXP_EQ_LU(Locked, MMAPLEN);
107
108 SAFE_MUNLOCK(buf, MMAPLEN);
109 SAFE_MUNMAP(buf, MMAPLEN);
110 }
111
112 static struct tst_test test = {
113 .test_all = verify_mlock,
114 };
115