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 55 #define MAPS_FILE "/proc/self/maps" 56 57 char *TCID = "vma01"; 58 int TST_TOTAL = 1; 59 60 static void check_vma(void); 61 static void create_bighole(void); 62 static void *get_end_addr(void *addr_s); 63 static void check_status(int status); 64 static void setup(void); 65 static void cleanup(void); 66 67 static unsigned long ps; 68 static void *p; 69 70 int main(int argc, char **argv) 71 { 72 int lc; 73 74 tst_parse_opts(argc, argv, NULL, NULL); 75 76 ps = sysconf(_SC_PAGE_SIZE); 77 setup(); 78 79 for (lc = 0; TEST_LOOPING(lc); lc++) { 80 tst_count = 0; 81 82 check_vma(); 83 } 84 cleanup(); 85 tst_exit(); 86 } 87 88 static void check_vma(void) 89 { 90 int status; 91 int topdown; 92 void *t, *u, *x; 93 94 create_bighole(); 95 t = mmap(p, 3 * ps, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); 96 if (t == MAP_FAILED) 97 tst_brkm(TBROK | TERRNO, cleanup, "mmap"); 98 memset(t, 1, ps); 99 100 switch (fork()) { 101 case -1: 102 tst_brkm(TBROK | TERRNO, cleanup, "fork"); 103 case 0: 104 memset(t, 2, ps); 105 u = mmap(t + 3 * ps, 3 * ps, PROT_WRITE, 106 MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); 107 if (u == MAP_FAILED) { 108 perror("mmap"); 109 exit(255); 110 } 111 topdown = (u > t) ? 0 : 1; 112 printf("parent: t = %p\n", t); 113 printf("child : u = %p\n", u); 114 memset(u, 2, ps); 115 116 if (topdown) { 117 x = get_end_addr(u); 118 printf("child : x = %p\n", x); 119 if (x == t + 3 * ps) 120 exit(1); 121 else if (x == t && get_end_addr(x) == t + 3 * ps) 122 exit(0); 123 } else { 124 x = get_end_addr(t); 125 printf("child : x = %p\n", x); 126 if (x == t + 6 * ps) 127 exit(1); 128 else if (x == u && get_end_addr(x) == t + 6 * ps) 129 exit(0); 130 } 131 exit(255); 132 default: 133 if (waitpid(-1, &status, 0) == -1) 134 tst_brkm(TBROK | TERRNO, cleanup, "waitpid"); 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 if (munmap(t, 9 * ps) == -1) 159 tst_brkm(TBROK | TERRNO, cleanup, "munmap"); 160 } 161 162 static void *get_end_addr(void *addr_s) 163 { 164 FILE *fp; 165 void *s, *t; 166 char buf[BUFSIZ]; 167 168 fp = fopen(MAPS_FILE, "r"); 169 if (fp == NULL) 170 tst_brkm(TBROK | TERRNO, cleanup, "fopen"); 171 while (fgets(buf, BUFSIZ, fp) != NULL) { 172 if (sscanf(buf, "%p-%p ", &s, &t) != 2) 173 continue; 174 if (addr_s == s) { 175 tst_resm(TINFO, "s = %p, t = %p", s, t); 176 fclose(fp); 177 return t; 178 } 179 } 180 fclose(fp); 181 tst_brkm(TBROK, cleanup, "no matched s = %p found.", addr_s); 182 } 183 184 static void check_status(int status) 185 { 186 switch (status) { 187 case 0: 188 tst_resm(TPASS, "two 3*ps VMAs found."); 189 break; 190 case 1: 191 if (tst_kvercmp(3, 0, 0) < 0) { 192 tst_resm(TCONF, "A single 6*ps VMA found. You may need" 193 " to back port kernel commit 965f55d " 194 "to fix this scalability issue."); 195 } else { 196 tst_resm(TFAIL, "A single 6*ps VMA found."); 197 } 198 break; 199 default: 200 tst_brkm(TBROK, cleanup, "unexpected VMA found."); 201 } 202 } 203 204 static void setup(void) 205 { 206 tst_sig(FORK, DEF_HANDLER, cleanup); 207 208 TEST_PAUSE; 209 } 210 211 static void cleanup(void) 212 { 213 } 214
