lib/tsan/rtl/tsan_platform_linux.cc

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