1 /* 2 * vma01 - test not merging a VMA which cloned from parent process 3 * 4 * This program is used for testing the following upstream commit: 5 * 965f55dea0e331152fa53941a51e4e16f9f06fae 6 * 7 * The cloned VMA shares the anon_vma lock with the parent process's 8 * VMA. If we do the merge, more vmas (even the new range is only 9 * for current process) use the perent process's anon_vma lock. This 10 * introduces scalability issues. find_mergeable_anon_vma() already 11 * considers this case. 12 * 13 * This test program clones VMA and checks /proc/self/maps file, on 14 * an unpatched kernel, there is a single 6*ps VMA for the child 15 * like this: 16 * 17 * 7fee32989000-7fee3298f000 -w-p 00000000 00:00 0 18 * 19 * On a patched kernel, there are two 3*ps VMAs like this: 20 * 21 * 7f55bbd47000-7f55bbd4a000 -w-p 00000000 00:00 0 22 * 7f55bbd4a000-7f55bbd4d000 -w-p 00000000 00:00 0 23 * 24 * Copyright (C) 2011 Red Hat, Inc. 25 * This program is free software; you can redistribute it and/or 26 * modify it under the terms of version 2 of the GNU General Public 27 * License as published by the Free Software Foundation. 28 * 29 * This program is distributed in the hope that it would be useful, 30 * but WITHOUT ANY WARRANTY; without even the implied warranty of 31 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 32 * 33 * Further, this software is distributed without any warranty that it 34 * is free of the rightful claim of any third person regarding 35 * infringement or the like. Any license provided herein, whether 36 * implied or otherwise, applies only to this software file. Patent 37 * licenses, if any, provided herein do not apply to combinations of 38 * this program with other software, or any other product whatsoever. 39 * 40 * You should have received a copy of the GNU General Public License 41 * along with this program; if not, write the Free Software 42 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 43 * 02110-1301, USA. 44 */ 45 #include <sys/types.h> 46 #include <sys/mman.h> 47 #include <sys/wait.h> 48 #include <unistd.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 53 #include "test.h" 54 #include "safe_macros.h" 55 56 #define MAPS_FILE "/proc/self/maps" 57 58 char *TCID = "vma01"; 59 int TST_TOTAL = 1; 60 61 static void check_vma(void); 62 static void create_bighole(void); 63 static void *get_end_addr(void *addr_s); 64 static void check_status(int status); 65 static void setup(void); 66 static void cleanup(void); 67 68 static unsigned long ps; 69 static void *p; 70 71 int main(int argc, char **argv) 72 { 73 int lc; 74 75 tst_parse_opts(argc, argv, NULL, NULL); 76 77 ps = sysconf(_SC_PAGE_SIZE); 78 setup(); 79 80 for (lc = 0; TEST_LOOPING(lc); lc++) { 81 tst_count = 0; 82 83 check_vma(); 84 } 85 cleanup(); 86 tst_exit(); 87 } 88 89 static void check_vma(void) 90 { 91 int status; 92 int topdown; 93 void *t, *u, *x; 94 95 create_bighole(); 96 t = mmap(p, 3 * ps, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); 97 if (t == MAP_FAILED) 98 tst_brkm(TBROK | TERRNO, cleanup, "mmap"); 99 memset(t, 1, ps); 100 101 switch (fork()) { 102 case -1: 103 tst_brkm(TBROK | TERRNO, cleanup, "fork"); 104 case 0: 105 memset(t, 2, ps); 106 u = mmap(t + 3 * ps, 3 * ps, PROT_WRITE, 107 MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); 108 if (u == MAP_FAILED) { 109 perror("mmap"); 110 exit(255); 111 } 112 topdown = (u > t) ? 0 : 1; 113 printf("parent: t = %p\n", t); 114 printf("child : u = %p\n", u); 115 memset(u, 2, ps); 116 117 if (topdown) { 118 x = get_end_addr(u); 119 printf("child : x = %p\n", x); 120 if (x == t + 3 * ps) 121 exit(1); 122 else if (x == t && get_end_addr(x) == t + 3 * ps) 123 exit(0); 124 } else { 125 x = get_end_addr(t); 126 printf("child : x = %p\n", x); 127 if (x == t + 6 * ps) 128 exit(1); 129 else if (x == u && get_end_addr(x) == t + 6 * ps) 130 exit(0); 131 } 132 exit(255); 133 default: 134 SAFE_WAITPID(cleanup, -1, &status, 0); 135 if (!WIFEXITED(status)) 136 tst_brkm(TBROK, cleanup, "child exited abnormally."); 137 check_status(WEXITSTATUS(status)); 138 break; 139 } 140 } 141 142 static void create_bighole(void) 143 { 144 void *t; 145 146 /* 147 * |-3*ps-| 148 * |------|------|------| hole 149 * t p 150 * |======|------| top-down alloc 151 * |------|======| bottom-up alloc 152 */ 153 t = mmap(NULL, 9 * ps, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); 154 if (t == MAP_FAILED) 155 tst_brkm(TBROK | TERRNO, cleanup, "mmap"); 156 memset(t, 'a', ps); 157 p = t + 3 * ps; 158 SAFE_MUNMAP(cleanup, t, 9 * ps); 159 } 160 161 static void *get_end_addr(void *addr_s) 162 { 163 FILE *fp; 164 void *s, *t; 165 char buf[BUFSIZ]; 166 167 fp = fopen(MAPS_FILE, "r"); 168 if (fp == NULL) 169 tst_brkm(TBROK | TERRNO, cleanup, "fopen"); 170 while (fgets(buf, BUFSIZ, fp) != NULL) { 171 if (sscanf(buf, "%p-%p ", &s, &t) != 2) 172 continue; 173 if (addr_s == s) { 174 tst_resm(TINFO, "s = %p, t = %p", s, t); 175 fclose(fp); 176 return t; 177 } 178 } 179 fclose(fp); 180 tst_brkm(TBROK, cleanup, "no matched s = %p found.", addr_s); 181 } 182 183 static void check_status(int status) 184 { 185 switch (status) { 186 case 0: 187 tst_resm(TPASS, "two 3*ps VMAs found."); 188 break; 189 case 1: 190 if (tst_kvercmp(3, 0, 0) < 0) { 191 tst_resm(TCONF, "A single 6*ps VMA found. You may need" 192 " to back port kernel commit 965f55d " 193 "to fix this scalability issue."); 194 } else { 195 tst_resm(TFAIL, "A single 6*ps VMA found."); 196 } 197 break; 198 default: 199 tst_brkm(TBROK, cleanup, "unexpected VMA found."); 200 } 201 } 202 203 static void setup(void) 204 { 205 tst_sig(FORK, DEF_HANDLER, cleanup); 206 207 TEST_PAUSE; 208 } 209 210 static void cleanup(void) 211 { 212 } 213
