1 //===-- tsan_platform_linux.cc --------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file is a part of ThreadSanitizer (TSan), a race detector. 11 // 12 // Linux-specific code. 13 //===----------------------------------------------------------------------===// 14 15 16 #include "sanitizer_common/sanitizer_platform.h" 17 #if SANITIZER_LINUX 18 19 #include "sanitizer_common/sanitizer_common.h" 20 #include "sanitizer_common/sanitizer_libc.h" 21 #include "sanitizer_common/sanitizer_procmaps.h" 22 #include "tsan_platform.h" 23 #include "tsan_rtl.h" 24 #include "tsan_flags.h" 25 26 #include <fcntl.h> 27 #include <pthread.h> 28 #include <signal.h> 29 #include <stdio.h> 30 #include <stdlib.h> 31 #include <string.h> 32 #include <stdarg.h> 33 #include <sys/mman.h> 34 #include <sys/prctl.h> 35 #include <sys/syscall.h> 36 #include <sys/time.h> 37 #include <sys/types.h> 38 #include <sys/resource.h> 39 #include <sys/stat.h> 40 #include <unistd.h> 41 #include <errno.h> 42 #include <sched.h> 43 #include <dlfcn.h> 44 #define __need_res_state 45 #include <resolv.h> 46 #include <malloc.h> 47 48 extern "C" struct mallinfo __libc_mallinfo(); 49 50 namespace __tsan { 51 52 const uptr kPageSize = 4096; 53 54 #ifndef TSAN_GO 55 ScopedInRtl::ScopedInRtl() 56 : thr_(cur_thread()) { 57 in_rtl_ = thr_->in_rtl; 58 thr_->in_rtl++; 59 errno_ = errno; 60 } 61 62 ScopedInRtl::~ScopedInRtl() { 63 thr_->in_rtl--; 64 errno = errno_; 65 CHECK_EQ(in_rtl_, thr_->in_rtl); 66 } 67 #else 68 ScopedInRtl::ScopedInRtl() { 69 } 70 71 ScopedInRtl::~ScopedInRtl() { 72 } 73 #endif 74 75 static bool ishex(char c) { 76 return (c >= '0' && c <= '9') 77 || (c >= 'a' && c <= 'f'); 78 } 79 80 static uptr readhex(const char *p) { 81 uptr v = 0; 82 for (; ishex(p[0]); p++) { 83 if (p[0] >= '0' && p[0] <= '9') 84 v = v * 16 + p[0] - '0'; 85 else 86 v = v * 16 + p[0] - 'a' + 10; 87 } 88 return v; 89 } 90 91 static uptr readdec(const char *p) { 92 uptr v = 0; 93 for (; p[0] >= '0' && p[0] <= '9' ; p++) 94 v = v * 10 + p[0] - '0'; 95 return v; 96 } 97 98 void WriteMemoryProfile(char *buf, uptr buf_size) { 99 char *smaps = 0; 100 uptr smaps_cap = 0; 101 uptr smaps_len = ReadFileToBuffer("/proc/self/smaps", 102 &smaps, &smaps_cap, 64<<20); 103 uptr mem[6] = {}; 104 uptr total = 0; 105 uptr start = 0; 106 bool file = false; 107 const char *pos = smaps; 108 while (pos < smaps + smaps_len) { 109 if (ishex(pos[0])) { 110 start = readhex(pos); 111 for (; *pos != '/' && *pos > '\n'; pos++) {} 112 file = *pos == '/'; 113 } else if (internal_strncmp(pos, "Rss:", 4) == 0) { 114 for (; *pos < '0' || *pos > '9'; pos++) {} 115 uptr rss = readdec(pos) * 1024; 116 total += rss; 117 start >>= 40; 118 if (start < 0x10) // shadow 119 mem[0] += rss; 120 else if (start >= 0x20 && start < 0x30) // compat modules 121 mem[file ? 1 : 2] += rss; 122 else if (start >= 0x7e) // modules 123 mem[file ? 1 : 2] += rss; 124 else if (start >= 0x60 && start < 0x62) // traces 125 mem[3] += rss; 126 else if (start >= 0x7d && start < 0x7e) // heap 127 mem[4] += rss; 128 else // other 129 mem[5] += rss; 130 } 131 while (*pos++ != '\n') {} 132 } 133 UnmapOrDie(smaps, smaps_cap); 134 char *buf_pos = buf; 135 char *buf_end = buf + buf_size; 136 buf_pos += internal_snprintf(buf_pos, buf_end - buf_pos, 137 "RSS %zd MB: shadow:%zd file:%zd mmap:%zd trace:%zd heap:%zd other:%zd\n", 138 total >> 20, mem[0] >> 20, mem[1] >> 20, mem[2] >> 20, 139 mem[3] >> 20, mem[4] >> 20, mem[5] >> 20); 140 struct mallinfo mi = __libc_mallinfo(); 141 buf_pos += internal_snprintf(buf_pos, buf_end - buf_pos, 142 "mallinfo: arena=%d mmap=%d fordblks=%d keepcost=%d\n", 143 mi.arena >> 20, mi.hblkhd >> 20, mi.fordblks >> 20, mi.keepcost >> 20); 144 } 145 146 void FlushShadowMemory() { 147 FlushUnneededShadowMemory(kLinuxShadowBeg, kLinuxShadowEnd - kLinuxShadowBeg); 148 } 149 150 #ifndef TSAN_GO 151 static void ProtectRange(uptr beg, uptr end) { 152 ScopedInRtl in_rtl; 153 CHECK_LE(beg, end); 154 if (beg == end) 155 return; 156 if (beg != (uptr)Mprotect(beg, end - beg)) { 157 Printf("FATAL: ThreadSanitizer can not protect [%zx,%zx]\n", beg, end); 158 Printf("FATAL: Make sure you are not using unlimited stack\n"); 159 Die(); 160 } 161 } 162 #endif 163 164 #ifndef TSAN_GO 165 // Mark shadow for .rodata sections with the special kShadowRodata marker. 166 // Accesses to .rodata can't race, so this saves time, memory and trace space. 167 static void MapRodata() { 168 // First create temp file. 169 const char *tmpdir = GetEnv("TMPDIR"); 170 if (tmpdir == 0) 171 tmpdir = GetEnv("TEST_TMPDIR"); 172 #ifdef P_tmpdir 173 if (tmpdir == 0) 174 tmpdir = P_tmpdir; 175 #endif 176 if (tmpdir == 0) 177 return; 178 char filename[256]; 179 internal_snprintf(filename, sizeof(filename), "%s/tsan.rodata.%d", 180 tmpdir, (int)internal_getpid()); 181 uptr openrv = internal_open(filename, O_RDWR | O_CREAT | O_EXCL, 0600); 182 if (internal_iserror(openrv)) 183 return; 184 fd_t fd = openrv; 185 // Fill the file with kShadowRodata. 186 const uptr kMarkerSize = 512 * 1024 / sizeof(u64); 187 InternalScopedBuffer<u64> marker(kMarkerSize); 188 for (u64 *p = marker.data(); p < marker.data() + kMarkerSize; p++) 189 *p = kShadowRodata; 190 internal_write(fd, marker.data(), marker.size()); 191 // Map the file into memory. 192 uptr page = internal_mmap(0, kPageSize, PROT_READ | PROT_WRITE, 193 MAP_PRIVATE | MAP_ANONYMOUS, fd, 0); 194 if (internal_iserror(page)) { 195 internal_close(fd); 196 internal_unlink(filename); 197 return; 198 } 199 // Map the file into shadow of .rodata sections. 200 MemoryMappingLayout proc_maps(/*cache_enabled*/true); 201 uptr start, end, offset, prot; 202 char name[128]; 203 while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name), &prot)) { 204 if (name[0] != 0 && name[0] != '[' 205 && (prot & MemoryMappingLayout::kProtectionRead) 206 && (prot & MemoryMappingLayout::kProtectionExecute) 207 && !(prot & MemoryMappingLayout::kProtectionWrite) 208 && IsAppMem(start)) { 209 // Assume it's .rodata 210 char *shadow_start = (char*)MemToShadow(start); 211 char *shadow_end = (char*)MemToShadow(end); 212 for (char *p = shadow_start; p < shadow_end; p += marker.size()) { 213 internal_mmap(p, Min<uptr>(marker.size(), shadow_end - p), 214 PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, 0); 215 } 216 } 217 } 218 internal_close(fd); 219 internal_unlink(filename); 220 } 221 222 void InitializeShadowMemory() { 223 uptr shadow = (uptr)MmapFixedNoReserve(kLinuxShadowBeg, 224 kLinuxShadowEnd - kLinuxShadowBeg); 225 if (shadow != kLinuxShadowBeg) { 226 Printf("FATAL: ThreadSanitizer can not mmap the shadow memory\n"); 227 Printf("FATAL: Make sure to compile with -fPIE and " 228 "to link with -pie (%p, %p).\n", shadow, kLinuxShadowBeg); 229 Die(); 230 } 231 const uptr kClosedLowBeg = 0x200000; 232 const uptr kClosedLowEnd = kLinuxShadowBeg - 1; 233 const uptr kClosedMidBeg = kLinuxShadowEnd + 1; 234 const uptr kClosedMidEnd = min(kLinuxAppMemBeg, kTraceMemBegin); 235 ProtectRange(kClosedLowBeg, kClosedLowEnd); 236 ProtectRange(kClosedMidBeg, kClosedMidEnd); 237 DPrintf("kClosedLow %zx-%zx (%zuGB)\n", 238 kClosedLowBeg, kClosedLowEnd, (kClosedLowEnd - kClosedLowBeg) >> 30); 239 DPrintf("kLinuxShadow %zx-%zx (%zuGB)\n", 240 kLinuxShadowBeg, kLinuxShadowEnd, 241 (kLinuxShadowEnd - kLinuxShadowBeg) >> 30); 242 DPrintf("kClosedMid %zx-%zx (%zuGB)\n", 243 kClosedMidBeg, kClosedMidEnd, (kClosedMidEnd - kClosedMidBeg) >> 30); 244 DPrintf("kLinuxAppMem %zx-%zx (%zuGB)\n", 245 kLinuxAppMemBeg, kLinuxAppMemEnd, 246 (kLinuxAppMemEnd - kLinuxAppMemBeg) >> 30); 247 DPrintf("stack %zx\n", (uptr)&shadow); 248 249 MapRodata(); 250 } 251 #endif 252 253 static uptr g_data_start; 254 static uptr g_data_end; 255 256 #ifndef TSAN_GO 257 static void CheckPIE() { 258 // Ensure that the binary is indeed compiled with -pie. 259 MemoryMappingLayout proc_maps(true); 260 uptr start, end; 261 if (proc_maps.Next(&start, &end, 262 /*offset*/0, /*filename*/0, /*filename_size*/0, 263 /*protection*/0)) { 264 if ((u64)start < kLinuxAppMemBeg) { 265 Printf("FATAL: ThreadSanitizer can not mmap the shadow memory (" 266 "something is mapped at 0x%zx < 0x%zx)\n", 267 start, kLinuxAppMemBeg); 268 Printf("FATAL: Make sure to compile with -fPIE" 269 " and to link with -pie.\n"); 270 Die(); 271 } 272 } 273 } 274 275 static void InitDataSeg() { 276 MemoryMappingLayout proc_maps(true); 277 uptr start, end, offset; 278 char name[128]; 279 bool prev_is_data = false; 280 while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name), 281 /*protection*/ 0)) { 282 DPrintf("%p-%p %p %s\n", start, end, offset, name); 283 bool is_data = offset != 0 && name[0] != 0; 284 // BSS may get merged with [heap] in /proc/self/maps. This is not very 285 // reliable. 286 bool is_bss = offset == 0 && 287 (name[0] == 0 || internal_strcmp(name, "[heap]") == 0) && prev_is_data; 288 if (g_data_start == 0 && is_data) 289 g_data_start = start; 290 if (is_bss) 291 g_data_end = end; 292 prev_is_data = is_data; 293 } 294 DPrintf("guessed data_start=%p data_end=%p\n", g_data_start, g_data_end); 295 CHECK_LT(g_data_start, g_data_end); 296 CHECK_GE((uptr)&g_data_start, g_data_start); 297 CHECK_LT((uptr)&g_data_start, g_data_end); 298 } 299 300 #endif // #ifndef TSAN_GO 301 302 static rlim_t getlim(int res) { 303 rlimit rlim; 304 CHECK_EQ(0, getrlimit(res, &rlim)); 305 return rlim.rlim_cur; 306 } 307 308 static void setlim(int res, rlim_t lim) { 309 // The following magic is to prevent clang from replacing it with memset. 310 volatile rlimit rlim; 311 rlim.rlim_cur = lim; 312 rlim.rlim_max = lim; 313 setrlimit(res, (rlimit*)&rlim); 314 } 315 316 const char *InitializePlatform() { 317 void *p = 0; 318 if (sizeof(p) == 8) { 319 // Disable core dumps, dumping of 16TB usually takes a bit long. 320 setlim(RLIMIT_CORE, 0); 321 } 322 323 // Go maps shadow memory lazily and works fine with limited address space. 324 // Unlimited stack is not a problem as well, because the executable 325 // is not compiled with -pie. 326 if (kCppMode) { 327 bool reexec = false; 328 // TSan doesn't play well with unlimited stack size (as stack 329 // overlaps with shadow memory). If we detect unlimited stack size, 330 // we re-exec the program with limited stack size as a best effort. 331 if (getlim(RLIMIT_STACK) == (rlim_t)-1) { 332 const uptr kMaxStackSize = 32 * 1024 * 1024; 333 Report("WARNING: Program is run with unlimited stack size, which " 334 "wouldn't work with ThreadSanitizer.\n"); 335 Report("Re-execing with stack size limited to %zd bytes.\n", 336 kMaxStackSize); 337 SetStackSizeLimitInBytes(kMaxStackSize); 338 reexec = true; 339 } 340 341 if (getlim(RLIMIT_AS) != (rlim_t)-1) { 342 Report("WARNING: Program is run with limited virtual address space," 343 " which wouldn't work with ThreadSanitizer.\n"); 344 Report("Re-execing with unlimited virtual address space.\n"); 345 setlim(RLIMIT_AS, -1); 346 reexec = true; 347 } 348 if (reexec) 349 ReExec(); 350 } 351 352 #ifndef TSAN_GO 353 CheckPIE(); 354 InitTlsSize(); 355 InitDataSeg(); 356 #endif 357 return GetEnv(kTsanOptionsEnv); 358 } 359 360 bool IsGlobalVar(uptr addr) { 361 return g_data_start && addr >= g_data_start && addr < g_data_end; 362 } 363 364 #ifndef TSAN_GO 365 int ExtractResolvFDs(void *state, int *fds, int nfd) { 366 int cnt = 0; 367 __res_state *statp = (__res_state*)state; 368 for (int i = 0; i < MAXNS && cnt < nfd; i++) { 369 if (statp->_u._ext.nsaddrs[i] && statp->_u._ext.nssocks[i] != -1) 370 fds[cnt++] = statp->_u._ext.nssocks[i]; 371 } 372 return cnt; 373 } 374 #endif 375 376 377 } // namespace __tsan 378 379 #endif // SANITIZER_LINUX 380
