libsanitizer/tsan/tsan_platform_linux.cc

   1 //===-- tsan_platform_linux.cc --------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of ThreadSanitizer (TSan), a race detector.
   9 //
  10 // Linux- and FreeBSD-specific code.
  11 //===----------------------------------------------------------------------===//
  12
  13
  14 #include "sanitizer_common/sanitizer_platform.h"
  15 #if SANITIZER_LINUX || SANITIZER_FREEBSD
  16
  17 #include "sanitizer_common/sanitizer_common.h"
  18 #include "sanitizer_common/sanitizer_libc.h"
  19 #include "sanitizer_common/sanitizer_procmaps.h"
  20 #include "sanitizer_common/sanitizer_stoptheworld.h"
  21 #include "sanitizer_common/sanitizer_stackdepot.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/syscall.h>
  35 #include <sys/socket.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 #if SANITIZER_LINUX
  45 #define __need_res_state
  46 #include <resolv.h>
  47 #endif
  48
  49 #ifdef sa_handler
  50 # undef sa_handler
  51 #endif
  52
  53 #ifdef sa_sigaction
  54 # undef sa_sigaction
  55 #endif
  56
  57 #if SANITIZER_FREEBSD
  58 extern "C" void *__libc_stack_end;
  59 void *__libc_stack_end = 0;
  60 #endif
  61
  62 namespace __tsan {
  63
  64 static uptr g_data_start;
  65 static uptr g_data_end;
  66
  67 const uptr kPageSize = 4096;
  68
  69 enum {
  70   MemTotal  = 0,
  71   MemShadow = 1,
  72   MemMeta   = 2,
  73   MemFile   = 3,
  74   MemMmap   = 4,
  75   MemTrace  = 5,
  76   MemHeap   = 6,
  77   MemOther  = 7,
  78   MemCount  = 8,
  79 };
  80
  81 void FillProfileCallback(uptr p, uptr rss, bool file,
  82                          uptr *mem, uptr stats_size) {
  83   mem[MemTotal] += rss;
  84   if (p >= kShadowBeg && p < kShadowEnd)
  85     mem[MemShadow] += rss;
  86   else if (p >= kMetaShadowBeg && p < kMetaShadowEnd)
  87     mem[MemMeta] += rss;
  88 #ifndef TSAN_GO
  89   else if (p >= kHeapMemBeg && p < kHeapMemEnd)
  90     mem[MemHeap] += rss;
  91   else if (p >= kLoAppMemBeg && p < kLoAppMemEnd)
  92     mem[file ? MemFile : MemMmap] += rss;
  93   else if (p >= kHiAppMemBeg && p < kHiAppMemEnd)
  94     mem[file ? MemFile : MemMmap] += rss;
  95 #else
  96   else if (p >= kAppMemBeg && p < kAppMemEnd)
  97     mem[file ? MemFile : MemMmap] += rss;
  98 #endif
  99   else if (p >= kTraceMemBeg && p < kTraceMemEnd)
 100     mem[MemTrace] += rss;
 101   else
 102     mem[MemOther] += rss;
 103 }
 104
 105 void WriteMemoryProfile(char *buf, uptr buf_size, uptr nthread, uptr nlive) {
 106   uptr mem[MemCount] = {};
 107   __sanitizer::GetMemoryProfile(FillProfileCallback, mem, 7);
 108   StackDepotStats *stacks = StackDepotGetStats();
 109   internal_snprintf(buf, buf_size,
 110       "RSS %zd MB: shadow:%zd meta:%zd file:%zd mmap:%zd"
 111       " trace:%zd heap:%zd other:%zd stacks=%zd[%zd] nthr=%zd/%zd\n",
 112       mem[MemTotal] >> 20, mem[MemShadow] >> 20, mem[MemMeta] >> 20,
 113       mem[MemFile] >> 20, mem[MemMmap] >> 20, mem[MemTrace] >> 20,
 114       mem[MemHeap] >> 20, mem[MemOther] >> 20,
 115       stacks->allocated >> 20, stacks->n_uniq_ids,
 116       nlive, nthread);
 117 }
 118
 119 uptr GetRSS() {
 120   uptr fd = OpenFile("/proc/self/statm", false);
 121   if ((sptr)fd < 0)
 122     return 0;
 123   char buf[64];
 124   uptr len = internal_read(fd, buf, sizeof(buf) - 1);
 125   internal_close(fd);
 126   if ((sptr)len <= 0)
 127     return 0;
 128   buf[len] = 0;
 129   // The format of the file is:
 130   // 1084 89 69 11 0 79 0
 131   // We need the second number which is RSS in 4K units.
 132   char *pos = buf;
 133   // Skip the first number.
 134   while (*pos >= '0' && *pos <= '9')
 135     pos++;
 136   // Skip whitespaces.
 137   while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
 138     pos++;
 139   // Read the number.
 140   uptr rss = 0;
 141   while (*pos >= '0' && *pos <= '9')
 142     rss = rss * 10 + *pos++ - '0';
 143   return rss * 4096;
 144 }
 145
 146 #if SANITIZER_LINUX
 147 void FlushShadowMemoryCallback(
 148     const SuspendedThreadsList &suspended_threads_list,
 149     void *argument) {
 150   FlushUnneededShadowMemory(kShadowBeg, kShadowEnd - kShadowBeg);
 151 }
 152 #endif
 153
 154 void FlushShadowMemory() {
 155 #if SANITIZER_LINUX
 156   StopTheWorld(FlushShadowMemoryCallback, 0);
 157 #endif
 158 }
 159
 160 #ifndef TSAN_GO
 161 static void ProtectRange(uptr beg, uptr end) {
 162   CHECK_LE(beg, end);
 163   if (beg == end)
 164     return;
 165   if (beg != (uptr)Mprotect(beg, end - beg)) {
 166     Printf("FATAL: ThreadSanitizer can not protect [%zx,%zx]\n", beg, end);
 167     Printf("FATAL: Make sure you are not using unlimited stack\n");
 168     Die();
 169   }
 170 }
 171
 172 // Mark shadow for .rodata sections with the special kShadowRodata marker.
 173 // Accesses to .rodata can't race, so this saves time, memory and trace space.
 174 static void MapRodata() {
 175   // First create temp file.
 176   const char *tmpdir = GetEnv("TMPDIR");
 177   if (tmpdir == 0)
 178     tmpdir = GetEnv("TEST_TMPDIR");
 179 #ifdef P_tmpdir
 180   if (tmpdir == 0)
 181     tmpdir = P_tmpdir;
 182 #endif
 183   if (tmpdir == 0)
 184     return;
 185   char name[256];
 186   internal_snprintf(name, sizeof(name), "%s/tsan.rodata.%d",
 187                     tmpdir, (int)internal_getpid());
 188   uptr openrv = internal_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
 189   if (internal_iserror(openrv))
 190     return;
 191   internal_unlink(name);  // Unlink it now, so that we can reuse the buffer.
 192   fd_t fd = openrv;
 193   // Fill the file with kShadowRodata.
 194   const uptr kMarkerSize = 512 * 1024 / sizeof(u64);
 195   InternalScopedBuffer<u64> marker(kMarkerSize);
 196   // volatile to prevent insertion of memset
 197   for (volatile u64 *p = marker.data(); p < marker.data() + kMarkerSize; p++)
 198     *p = kShadowRodata;
 199   internal_write(fd, marker.data(), marker.size());
 200   // Map the file into memory.
 201   uptr page = internal_mmap(0, kPageSize, PROT_READ | PROT_WRITE,
 202                             MAP_PRIVATE | MAP_ANONYMOUS, fd, 0);
 203   if (internal_iserror(page)) {
 204     internal_close(fd);
 205     return;
 206   }
 207   // Map the file into shadow of .rodata sections.
 208   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 209   uptr start, end, offset, prot;
 210   // Reusing the buffer 'name'.
 211   while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name), &prot)) {
 212     if (name[0] != 0 && name[0] != '['
 213         && (prot & MemoryMappingLayout::kProtectionRead)
 214         && (prot & MemoryMappingLayout::kProtectionExecute)
 215         && !(prot & MemoryMappingLayout::kProtectionWrite)
 216         && IsAppMem(start)) {
 217       // Assume it's .rodata
 218       char *shadow_start = (char*)MemToShadow(start);
 219       char *shadow_end = (char*)MemToShadow(end);
 220       for (char *p = shadow_start; p < shadow_end; p += marker.size()) {
 221         internal_mmap(p, Min<uptr>(marker.size(), shadow_end - p),
 222                       PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, 0);
 223       }
 224     }
 225   }
 226   internal_close(fd);
 227 }
 228
 229 void InitializeShadowMemory() {
 230   // Map memory shadow.
 231   uptr shadow = (uptr)MmapFixedNoReserve(kShadowBeg,
 232     kShadowEnd - kShadowBeg);
 233   if (shadow != kShadowBeg) {
 234     Printf("FATAL: ThreadSanitizer can not mmap the shadow memory\n");
 235     Printf("FATAL: Make sure to compile with -fPIE and "
 236                "to link with -pie (%p, %p).\n", shadow, kShadowBeg);
 237     Die();
 238   }
 239   // This memory range is used for thread stacks and large user mmaps.
 240   // Frequently a thread uses only a small part of stack and similarly
 241   // a program uses a small part of large mmap. On some programs
 242   // we see 20% memory usage reduction without huge pages for this range.
 243 #ifdef MADV_NOHUGEPAGE
 244   madvise((void*)MemToShadow(0x7f0000000000ULL),
 245       0x10000000000ULL * kShadowMultiplier, MADV_NOHUGEPAGE);
 246 #endif
 247   DPrintf("memory shadow: %zx-%zx (%zuGB)\n",
 248       kShadowBeg, kShadowEnd,
 249       (kShadowEnd - kShadowBeg) >> 30);
 250
 251   // Map meta shadow.
 252   uptr meta_size = kMetaShadowEnd - kMetaShadowBeg;
 253   uptr meta = (uptr)MmapFixedNoReserve(kMetaShadowBeg, meta_size);
 254   if (meta != kMetaShadowBeg) {
 255     Printf("FATAL: ThreadSanitizer can not mmap the shadow memory\n");
 256     Printf("FATAL: Make sure to compile with -fPIE and "
 257                "to link with -pie (%p, %p).\n", meta, kMetaShadowBeg);
 258     Die();
 259   }
 260   DPrintf("meta shadow: %zx-%zx (%zuGB)\n",
 261       meta, meta + meta_size, meta_size >> 30);
 262
 263   MapRodata();
 264 }
 265
 266 static void InitDataSeg() {
 267   MemoryMappingLayout proc_maps(true);
 268   uptr start, end, offset;
 269   char name[128];
 270 #if SANITIZER_FREEBSD
 271   // On FreeBSD BSS is usually the last block allocated within the
 272   // low range and heap is the last block allocated within the range
 273   // 0x800000000-0x8ffffffff.
 274   while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name),
 275                         /*protection*/ 0)) {
 276     DPrintf("%p-%p %p %s\n", start, end, offset, name);
 277     if ((start & 0xffff00000000ULL) == 0 && (end & 0xffff00000000ULL) == 0 &&
 278         name[0] == '\0') {
 279       g_data_start = start;
 280       g_data_end = end;
 281     }
 282   }
 283 #else
 284   bool prev_is_data = false;
 285   while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name),
 286                         /*protection*/ 0)) {
 287     DPrintf("%p-%p %p %s\n", start, end, offset, name);
 288     bool is_data = offset != 0 && name[0] != 0;
 289     // BSS may get merged with [heap] in /proc/self/maps. This is not very
 290     // reliable.
 291     bool is_bss = offset == 0 &&
 292       (name[0] == 0 || internal_strcmp(name, "[heap]") == 0) && prev_is_data;
 293     if (g_data_start == 0 && is_data)
 294       g_data_start = start;
 295     if (is_bss)
 296       g_data_end = end;
 297     prev_is_data = is_data;
 298   }
 299 #endif
 300   DPrintf("guessed data_start=%p data_end=%p\n",  g_data_start, g_data_end);
 301   CHECK_LT(g_data_start, g_data_end);
 302   CHECK_GE((uptr)&g_data_start, g_data_start);
 303   CHECK_LT((uptr)&g_data_start, g_data_end);
 304 }
 305
 306 static void CheckAndProtect() {
 307   // Ensure that the binary is indeed compiled with -pie.
 308   MemoryMappingLayout proc_maps(true);
 309   uptr p, end;
 310   while (proc_maps.Next(&p, &end, 0, 0, 0, 0)) {
 311     if (IsAppMem(p))
 312       continue;
 313     if (p >= kHeapMemEnd &&
 314         p < kHeapMemEnd + PrimaryAllocator::AdditionalSize())
 315       continue;
 316     if (p >= 0xf000000000000000ull)  // vdso
 317       break;
 318     Printf("FATAL: ThreadSanitizer: unexpected memory mapping %p-%p\n", p, end);
 319     Die();
 320   }
 321
 322   ProtectRange(kLoAppMemEnd, kShadowBeg);
 323   ProtectRange(kShadowEnd, kMetaShadowBeg);
 324   ProtectRange(kMetaShadowEnd, kTraceMemBeg);
 325   ProtectRange(kTraceMemEnd, kHeapMemBeg);
 326   ProtectRange(kHeapMemEnd + PrimaryAllocator::AdditionalSize(), kHiAppMemBeg);
 327 }
 328 #endif  // #ifndef TSAN_GO
 329
 330 void InitializePlatform() {
 331   DisableCoreDumperIfNecessary();
 332
 333   // Go maps shadow memory lazily and works fine with limited address space.
 334   // Unlimited stack is not a problem as well, because the executable
 335   // is not compiled with -pie.
 336   if (kCppMode) {
 337     bool reexec = false;
 338     // TSan doesn't play well with unlimited stack size (as stack
 339     // overlaps with shadow memory). If we detect unlimited stack size,
 340     // we re-exec the program with limited stack size as a best effort.
 341     if (StackSizeIsUnlimited()) {
 342       const uptr kMaxStackSize = 32 * 1024 * 1024;
 343       VReport(1, "Program is run with unlimited stack size, which wouldn't "
 344                  "work with ThreadSanitizer.\n"
 345                  "Re-execing with stack size limited to %zd bytes.\n",
 346               kMaxStackSize);
 347       SetStackSizeLimitInBytes(kMaxStackSize);
 348       reexec = true;
 349     }
 350
 351     if (!AddressSpaceIsUnlimited()) {
 352       Report("WARNING: Program is run with limited virtual address space,"
 353              " which wouldn't work with ThreadSanitizer.\n");
 354       Report("Re-execing with unlimited virtual address space.\n");
 355       SetAddressSpaceUnlimited();
 356       reexec = true;
 357     }
 358     if (reexec)
 359       ReExec();
 360   }
 361
 362 #ifndef TSAN_GO
 363   CheckAndProtect();
 364   InitTlsSize();
 365   InitDataSeg();
 366 #endif
 367 }
 368
 369 bool IsGlobalVar(uptr addr) {
 370   return g_data_start && addr >= g_data_start && addr < g_data_end;
 371 }
 372
 373 #ifndef TSAN_GO
 374 // Extract file descriptors passed to glibc internal __res_iclose function.
 375 // This is required to properly "close" the fds, because we do not see internal
 376 // closes within glibc. The code is a pure hack.
 377 int ExtractResolvFDs(void *state, int *fds, int nfd) {
 378 #if SANITIZER_LINUX
 379   int cnt = 0;
 380   __res_state *statp = (__res_state*)state;
 381   for (int i = 0; i < MAXNS && cnt < nfd; i++) {
 382     if (statp->_u._ext.nsaddrs[i] && statp->_u._ext.nssocks[i] != -1)
 383       fds[cnt++] = statp->_u._ext.nssocks[i];
 384   }
 385   return cnt;
 386 #else
 387   return 0;
 388 #endif
 389 }
 390
 391 // Extract file descriptors passed via UNIX domain sockets.
 392 // This is requried to properly handle "open" of these fds.
 393 // see 'man recvmsg' and 'man 3 cmsg'.
 394 int ExtractRecvmsgFDs(void *msgp, int *fds, int nfd) {
 395   int res = 0;
 396   msghdr *msg = (msghdr*)msgp;
 397   struct cmsghdr *cmsg = CMSG_FIRSTHDR(msg);
 398   for (; cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 399     if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS)
 400       continue;
 401     int n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(fds[0]);
 402     for (int i = 0; i < n; i++) {
 403       fds[res++] = ((int*)CMSG_DATA(cmsg))[i];
 404       if (res == nfd)
 405         return res;
 406     }
 407   }
 408   return res;
 409 }
 410
 411 int call_pthread_cancel_with_cleanup(int(*fn)(void *c, void *m,
 412     void *abstime), void *c, void *m, void *abstime,
 413     void(*cleanup)(void *arg), void *arg) {
 414   // pthread_cleanup_push/pop are hardcore macros mess.
 415   // We can't intercept nor call them w/o including pthread.h.
 416   int res;
 417   pthread_cleanup_push(cleanup, arg);
 418   res = fn(c, m, abstime);
 419   pthread_cleanup_pop(0);
 420   return res;
 421 }
 422 #endif
 423
 424 }  // namespace __tsan
 425
 426 #endif  // SANITIZER_LINUX || SANITIZER_FREEBSD