tsan_platform_linux.cc revision 4dc30820d34372c419fd44dda2bdb6383a480ce7 
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
44extern "C" int arch_prctl(int code, __sanitizer::uptr *addr);
45
46namespace __tsan {
47
48#ifndef TSAN_GO
49ScopedInRtl::ScopedInRtl()
50    : thr_(cur_thread()) {
51  in_rtl_ = thr_->in_rtl;
52  thr_->in_rtl++;
53  errno_ = errno;
54}
55
56ScopedInRtl::~ScopedInRtl() {
57  thr_->in_rtl--;
58  errno = errno_;
59  CHECK_EQ(in_rtl_, thr_->in_rtl);
60}
61#else
62ScopedInRtl::ScopedInRtl() {
63}
64
65ScopedInRtl::~ScopedInRtl() {
66}
67#endif
68
69uptr GetShadowMemoryConsumption() {
70  return 0;
71}
72
73void FlushShadowMemory() {
74  madvise((void*)kLinuxShadowBeg,
75          kLinuxShadowEnd - kLinuxShadowBeg,
76          MADV_DONTNEED);
77}
78
79#ifndef TSAN_GO
80static 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
94void 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
123static uptr g_data_start;
124static uptr g_data_end;
125
126#ifndef TSAN_GO
127static 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
144static 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
168static uptr g_tls_size;
169
170#ifdef __i386__
171# define INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
172#else
173# define INTERNAL_FUNCTION
174#endif
175extern "C" void _dl_get_tls_static_info(size_t*, size_t*)
176    __attribute__((weak)) INTERNAL_FUNCTION;
177
178static 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
195static rlim_t getlim(int res) {
196  rlimit rlim;
197  CHECK_EQ(0, getrlimit(res, &rlim));
198  return rlim.rlim_cur;
199}
200
201static 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
209const 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",
229             kMaxStackSize);
230      SetStackSizeLimitInBytes(kMaxStackSize);
231      reexec = true;
232    }
233
234    if (getlim(RLIMIT_AS) != (rlim_t)-1) {
235      Report("WARNING: Program is run with limited virtual address space,"
236             " which wouldn't work with ThreadSanitizer.\n");
237      Report("Re-execing with unlimited virtual address space.\n");
238      setlim(RLIMIT_AS, -1);
239      reexec = true;
240    }
241    if (reexec)
242      ReExec();
243  }
244
245#ifndef TSAN_GO
246  CheckPIE();
247  g_tls_size = (uptr)InitTlsSize();
248  InitDataSeg();
249#endif
250  return getenv(kTsanOptionsEnv);
251}
252
253void FinalizePlatform() {
254  fflush(0);
255}
256
257uptr GetTlsSize() {
258#ifndef TSAN_GO
259  return g_tls_size;
260#else
261  return 0;
262#endif
263}
264
265void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
266                          uptr *tls_addr, uptr *tls_size) {
267#ifndef TSAN_GO
268  arch_prctl(ARCH_GET_FS, tls_addr);
269  *tls_addr -= g_tls_size;
270  *tls_size = g_tls_size;
271
272  uptr stack_top, stack_bottom;
273  GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
274  *stk_addr = stack_bottom;
275  *stk_size = stack_top - stack_bottom;
276
277  if (!main) {
278    // If stack and tls intersect, make them non-intersecting.
279    if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
280      CHECK_GT(*tls_addr + *tls_size, *stk_addr);
281      CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
282      *stk_size -= *tls_size;
283      *tls_addr = *stk_addr + *stk_size;
284    }
285  }
286#else
287  *stk_addr = 0;
288  *stk_size = 0;
289  *tls_addr = 0;
290  *tls_size = 0;
291#endif
292}
293
294bool IsGlobalVar(uptr addr) {
295  return g_data_start && addr >= g_data_start && addr < g_data_end;
296}
297
298}  // namespace __tsan
299
300#endif  // #ifdef __linux__
301