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 #ifdef __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 "tsan_platform.h"
  21 #include "tsan_rtl.h"
  22 #include "tsan_flags.h"
  23
  24 #include <asm/prctl.h>
  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/time.h>
  36 #include <sys/types.h>
  37 #include <sys/resource.h>
  38 #include <sys/stat.h>
  39 #include <unistd.h>
  40 #include <errno.h>
  41 #include <sched.h>
  42 #include <dlfcn.h>
  43
  44 extern "C" int arch_prctl(int code, __sanitizer::uptr *addr);
  45
  46 namespace __tsan {
  47
  48 #ifndef TSAN_GO
  49 ScopedInRtl::ScopedInRtl()
  50     : thr_(cur_thread()) {
  51   in_rtl_ = thr_->in_rtl;
  52   thr_->in_rtl++;
  53   errno_ = errno;
  54 }
  55
  56 ScopedInRtl::~ScopedInRtl() {
  57   thr_->in_rtl--;
  58   errno = errno_;
  59   CHECK_EQ(in_rtl_, thr_->in_rtl);
  60 }
  61 #else
  62 ScopedInRtl::ScopedInRtl() {
  63 }
  64
  65 ScopedInRtl::~ScopedInRtl() {
  66 }
  67 #endif
  68
  69 uptr GetShadowMemoryConsumption() {
  70   return 0;
  71 }
  72
  73 void FlushShadowMemory() {
  74   madvise((void*)kLinuxShadowBeg,
  75           kLinuxShadowEnd - kLinuxShadowBeg,
  76           MADV_DONTNEED);
  77 }
  78
  79 #ifndef TSAN_GO
  80 static void ProtectRange(uptr beg, uptr end) {
  81   ScopedInRtl in_rtl;
  82   CHECK_LE(beg, end);
  83   if (beg == end)
  84     return;
  85   if (beg != (uptr)Mprotect(beg, end - beg)) {
  86     Printf("FATAL: ThreadSanitizer can not protect [%zx,%zx]\n", beg, end);
  87     Printf("FATAL: Make sure you are not using unlimited stack\n");
  88     Die();
  89   }
  90 }
  91 #endif
  92
  93 #ifndef TSAN_GO
  94 void InitializeShadowMemory() {
  95   uptr shadow = (uptr)MmapFixedNoReserve(kLinuxShadowBeg,
  96     kLinuxShadowEnd - kLinuxShadowBeg);
  97   if (shadow != kLinuxShadowBeg) {
  98     Printf("FATAL: ThreadSanitizer can not mmap the shadow memory\n");
  99     Printf("FATAL: Make sure to compile with -fPIE and "
 100                "to link with -pie (%p, %p).\n", shadow, kLinuxShadowBeg);
 101     Die();
 102   }
 103   const uptr kClosedLowBeg  = 0x200000;
 104   const uptr kClosedLowEnd  = kLinuxShadowBeg - 1;
 105   const uptr kClosedMidBeg = kLinuxShadowEnd + 1;
 106   const uptr kClosedMidEnd = min(kLinuxAppMemBeg, kTraceMemBegin);
 107   ProtectRange(kClosedLowBeg, kClosedLowEnd);
 108   ProtectRange(kClosedMidBeg, kClosedMidEnd);
 109   DPrintf("kClosedLow   %zx-%zx (%zuGB)\n",
 110       kClosedLowBeg, kClosedLowEnd, (kClosedLowEnd - kClosedLowBeg) >> 30);
 111   DPrintf("kLinuxShadow %zx-%zx (%zuGB)\n",
 112       kLinuxShadowBeg, kLinuxShadowEnd,
 113       (kLinuxShadowEnd - kLinuxShadowBeg) >> 30);
 114   DPrintf("kClosedMid   %zx-%zx (%zuGB)\n",
 115       kClosedMidBeg, kClosedMidEnd, (kClosedMidEnd - kClosedMidBeg) >> 30);
 116   DPrintf("kLinuxAppMem %zx-%zx (%zuGB)\n",
 117       kLinuxAppMemBeg, kLinuxAppMemEnd,
 118       (kLinuxAppMemEnd - kLinuxAppMemBeg) >> 30);
 119   DPrintf("stack        %zx\n", (uptr)&shadow);
 120 }
 121 #endif
 122
 123 static uptr g_data_start;
 124 static uptr g_data_end;
 125
 126 #ifndef TSAN_GO
 127 static void CheckPIE() {
 128   // Ensure that the binary is indeed compiled with -pie.
 129   MemoryMappingLayout proc_maps;
 130   uptr start, end;
 131   if (proc_maps.Next(&start, &end,
 132                      /*offset*/0, /*filename*/0, /*filename_size*/0)) {
 133     if ((u64)start < kLinuxAppMemBeg) {
 134       Printf("FATAL: ThreadSanitizer can not mmap the shadow memory ("
 135              "something is mapped at 0x%zx < 0x%zx)\n",
 136              start, kLinuxAppMemBeg);
 137       Printf("FATAL: Make sure to compile with -fPIE"
 138              " and to link with -pie.\n");
 139       Die();
 140     }
 141   }
 142 }
 143
 144 static void InitDataSeg() {
 145   MemoryMappingLayout proc_maps;
 146   uptr start, end, offset;
 147   char name[128];
 148   bool prev_is_data = false;
 149   while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name))) {
 150     DPrintf("%p-%p %p %s\n", start, end, offset, name);
 151     bool is_data = offset != 0 && name[0] != 0;
 152     // BSS may get merged with [heap] in /proc/self/maps. This is not very
 153     // reliable.
 154     bool is_bss = offset == 0 &&
 155       (name[0] == 0 || internal_strcmp(name, "[heap]") == 0) && prev_is_data;
 156     if (g_data_start == 0 && is_data)
 157       g_data_start = start;
 158     if (is_bss)
 159       g_data_end = end;
 160     prev_is_data = is_data;
 161   }
 162   DPrintf("guessed data_start=%p data_end=%p\n",  g_data_start, g_data_end);
 163   CHECK_LT(g_data_start, g_data_end);
 164   CHECK_GE((uptr)&g_data_start, g_data_start);
 165   CHECK_LT((uptr)&g_data_start, g_data_end);
 166 }
 167
 168 static uptr g_tls_size;
 169
 170 #ifdef __i386__
 171 # define INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
 172 #else
 173 # define INTERNAL_FUNCTION
 174 #endif
 175 extern "C" void _dl_get_tls_static_info(size_t*, size_t*)
 176     __attribute__((weak)) INTERNAL_FUNCTION;
 177
 178 static int InitTlsSize() {
 179   typedef void (*get_tls_func)(size_t*, size_t*) INTERNAL_FUNCTION;
 180   get_tls_func get_tls = &_dl_get_tls_static_info;
 181   if (get_tls == 0) {
 182     void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
 183     CHECK_EQ(sizeof(get_tls), sizeof(get_tls_static_info_ptr));
 184     internal_memcpy(&get_tls, &get_tls_static_info_ptr,
 185                     sizeof(get_tls_static_info_ptr));
 186   }
 187   CHECK_NE(get_tls, 0);
 188   size_t tls_size = 0;
 189   size_t tls_align = 0;
 190   get_tls(&tls_size, &tls_align);
 191   return tls_size;
 192 }
 193 #endif  // #ifndef TSAN_GO
 194
 195 static rlim_t getlim(int res) {
 196   rlimit rlim;
 197   CHECK_EQ(0, getrlimit(res, &rlim));
 198   return rlim.rlim_cur;
 199 }
 200
 201 static void setlim(int res, rlim_t lim) {
 202   // The following magic is to prevent clang from replacing it with memset.
 203   volatile rlimit rlim;
 204   rlim.rlim_cur = lim;
 205   rlim.rlim_max = lim;
 206   setrlimit(res, (rlimit*)&rlim);
 207 }
 208
 209 const char *InitializePlatform() {
 210   void *p = 0;
 211   if (sizeof(p) == 8) {
 212     // Disable core dumps, dumping of 16TB usually takes a bit long.
 213     setlim(RLIMIT_CORE, 0);
 214   }
 215
 216   // Go maps shadow memory lazily and works fine with limited address space.
 217   // Unlimited stack is not a problem as well, because the executable
 218   // is not compiled with -pie.
 219   if (kCppMode) {
 220     bool reexec = false;
 221     // TSan doesn't play well with unlimited stack size (as stack
 222     // overlaps with shadow memory). If we detect unlimited stack size,
 223     // we re-exec the program with limited stack size as a best effort.
 224     if (getlim(RLIMIT_STACK) == (rlim_t)-1) {
 225       const uptr kMaxStackSize = 32 * 1024 * 1024;
 226       Report("WARNING: Program is run with unlimited stack size, which "
 227              "wouldn't work with ThreadSanitizer.\n");
 228       Report("Re-execing with stack size limited to %zd bytes.\n", kMaxStackSize);
 229       SetStackSizeLimitInBytes(kMaxStackSize);
 230       reexec = true;
 231     }
 232
 233     if (getlim(RLIMIT_AS) != (rlim_t)-1) {
 234       Report("WARNING: Program is run with limited virtual address space, which "
 235              "wouldn't work with ThreadSanitizer.\n");
 236       Report("Re-execing with unlimited virtual address space.\n");
 237       setlim(RLIMIT_AS, -1);
 238       reexec = true;
 239     }
 240     if (reexec)
 241       ReExec();
 242   }
 243
 244 #ifndef TSAN_GO
 245   CheckPIE();
 246   g_tls_size = (uptr)InitTlsSize();
 247   InitDataSeg();
 248 #endif
 249   return getenv(kTsanOptionsEnv);
 250 }
 251
 252 void FinalizePlatform() {
 253   fflush(0);
 254 }
 255
 256 uptr GetTlsSize() {
 257 #ifndef TSAN_GO
 258   return g_tls_size;
 259 #else
 260   return 0;
 261 #endif
 262 }
 263
 264 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
 265                           uptr *tls_addr, uptr *tls_size) {
 266 #ifndef TSAN_GO
 267   arch_prctl(ARCH_GET_FS, tls_addr);
 268   *tls_addr -= g_tls_size;
 269   *tls_size = g_tls_size;
 270
 271   uptr stack_top, stack_bottom;
 272   GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
 273   *stk_addr = stack_bottom;
 274   *stk_size = stack_top - stack_bottom;
 275
 276   if (!main) {
 277     // If stack and tls intersect, make them non-intersecting.
 278     if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
 279       CHECK_GT(*tls_addr + *tls_size, *stk_addr);
 280       CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
 281       *stk_size -= *tls_size;
 282       *tls_addr = *stk_addr + *stk_size;
 283     }
 284   }
 285 #else
 286   *stk_addr = 0;
 287   *stk_size = 0;
 288   *tls_addr = 0;
 289   *tls_size = 0;
 290 #endif
 291 }
 292
 293 bool IsGlobalVar(uptr addr) {
 294   return g_data_start && addr >= g_data_start && addr < g_data_end;
 295 }
 296
 297 }  // namespace __tsan
 298
 299 #endif  // #ifdef __linux__