asan_thread.cc revision 5bcca4e33ececdddd8e9e07619c129e870492251 
1//===-- asan_thread.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 AddressSanitizer, an address sanity checker.
11//
12// Thread-related code.
13//===----------------------------------------------------------------------===//
14#include "asan_allocator.h"
15#include "asan_interceptors.h"
16#include "asan_procmaps.h"
17#include "asan_stack.h"
18#include "asan_thread.h"
19#include "asan_thread_registry.h"
20#include "asan_mapping.h"
21
22namespace __asan {
23
24AsanThread::AsanThread(LinkerInitialized x)
25    : fake_stack_(x),
26      malloc_storage_(x),
27      stats_(x) { }
28
29AsanThread *AsanThread::Create(int parent_tid, thread_callback_t start_routine,
30                               void *arg, AsanStackTrace *stack) {
31  uptr size = RoundUpTo(sizeof(AsanThread), kPageSize);
32  AsanThread *thread = (AsanThread*)AsanMmapSomewhereOrDie(size, __FUNCTION__);
33  thread->start_routine_ = start_routine;
34  thread->arg_ = arg;
35
36  AsanThreadSummary *summary = new AsanThreadSummary(parent_tid, stack);
37  summary->set_thread(thread);
38  thread->set_summary(summary);
39
40  return thread;
41}
42
43void AsanThreadSummary::TSDDtor(void *tsd) {
44  AsanThreadSummary *summary = (AsanThreadSummary*)tsd;
45  if (FLAG_v >= 1) {
46    Report("T%d TSDDtor\n", summary->tid());
47  }
48  if (summary->thread()) {
49    summary->thread()->Destroy();
50  }
51}
52
53void AsanThread::Destroy() {
54  if (FLAG_v >= 1) {
55    Report("T%d exited\n", tid());
56  }
57
58  asanThreadRegistry().UnregisterThread(this);
59  CHECK(summary()->thread() == 0);
60  // We also clear the shadow on thread destruction because
61  // some code may still be executing in later TSD destructors
62  // and we don't want it to have any poisoned stack.
63  ClearShadowForThreadStack();
64  fake_stack().Cleanup();
65  uptr size = RoundUpTo(sizeof(AsanThread), kPageSize);
66  AsanUnmapOrDie(this, size);
67}
68
69void AsanThread::Init() {
70  SetThreadStackTopAndBottom();
71  CHECK(AddrIsInMem(stack_bottom_));
72  CHECK(AddrIsInMem(stack_top_));
73  ClearShadowForThreadStack();
74  if (FLAG_v >= 1) {
75    int local = 0;
76    Report("T%d: stack [%p,%p) size 0x%zx; local=%p\n",
77           tid(), (void*)stack_bottom_, (void*)stack_top_,
78           stack_top_ - stack_bottom_, &local);
79  }
80  fake_stack_.Init(stack_size());
81}
82
83thread_return_t AsanThread::ThreadStart() {
84  Init();
85  if (FLAG_use_sigaltstack) SetAlternateSignalStack();
86
87  if (!start_routine_) {
88    // start_routine_ == 0 if we're on the main thread or on one of the
89    // OS X libdispatch worker threads. But nobody is supposed to call
90    // ThreadStart() for the worker threads.
91    CHECK(tid() == 0);
92    return 0;
93  }
94
95  thread_return_t res = start_routine_(arg_);
96  malloc_storage().CommitBack();
97  if (FLAG_use_sigaltstack) UnsetAlternateSignalStack();
98
99  this->Destroy();
100
101  return res;
102}
103
104void AsanThread::ClearShadowForThreadStack() {
105  PoisonShadow(stack_bottom_, stack_top_ - stack_bottom_, 0);
106}
107
108const char *AsanThread::GetFrameNameByAddr(uptr addr, uptr *offset) {
109  uptr bottom = 0;
110  bool is_fake_stack = false;
111  if (AddrIsInStack(addr)) {
112    bottom = stack_bottom();
113  } else {
114    bottom = fake_stack().AddrIsInFakeStack(addr);
115    CHECK(bottom);
116    is_fake_stack = true;
117  }
118  uptr aligned_addr = addr & ~(__WORDSIZE/8 - 1);  // align addr.
119  u8 *shadow_ptr = (u8*)MemToShadow(aligned_addr);
120  u8 *shadow_bottom = (u8*)MemToShadow(bottom);
121
122  while (shadow_ptr >= shadow_bottom &&
123      *shadow_ptr != kAsanStackLeftRedzoneMagic) {
124    shadow_ptr--;
125  }
126
127  while (shadow_ptr >= shadow_bottom &&
128      *shadow_ptr == kAsanStackLeftRedzoneMagic) {
129    shadow_ptr--;
130  }
131
132  if (shadow_ptr < shadow_bottom) {
133    *offset = 0;
134    return "UNKNOWN";
135  }
136
137  uptr* ptr = (uptr*)SHADOW_TO_MEM((uptr)(shadow_ptr + 1));
138  CHECK((ptr[0] == kCurrentStackFrameMagic) ||
139      (is_fake_stack && ptr[0] == kRetiredStackFrameMagic));
140  *offset = addr - (uptr)ptr;
141  return (const char*)ptr[1];
142}
143
144}  // namespace __asan
145