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