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_stack.h"
17 #include "asan_thread.h"
18 #include "asan_thread_registry.h"
19 #include "asan_mapping.h"
20 #include "sanitizer_common/sanitizer_common.h"
21
22 namespace __asan {
23
AsanThread(LinkerInitialized x)24 AsanThread::AsanThread(LinkerInitialized x)
25 : fake_stack_(x),
26 malloc_storage_(x),
27 stats_(x) { }
28
Create(u32 parent_tid,thread_callback_t start_routine,void * arg,StackTrace * stack)29 AsanThread *AsanThread::Create(u32 parent_tid, thread_callback_t start_routine,
30 void *arg, StackTrace *stack) {
31 uptr size = RoundUpTo(sizeof(AsanThread), kPageSize);
32 AsanThread *thread = (AsanThread*)MmapOrDie(size, __FUNCTION__);
33 thread->start_routine_ = start_routine;
34 thread->arg_ = arg;
35
36 const uptr kSummaryAllocSize = kPageSize;
37 CHECK_LE(sizeof(AsanThreadSummary), kSummaryAllocSize);
38 AsanThreadSummary *summary =
39 (AsanThreadSummary*)MmapOrDie(kPageSize, "AsanThreadSummary");
40 summary->Init(parent_tid, stack);
41 summary->set_thread(thread);
42 thread->set_summary(summary);
43
44 return thread;
45 }
46
TSDDtor(void * tsd)47 void AsanThreadSummary::TSDDtor(void *tsd) {
48 AsanThreadSummary *summary = (AsanThreadSummary*)tsd;
49 if (flags()->verbosity >= 1) {
50 Report("T%d TSDDtor\n", summary->tid());
51 }
52 if (summary->thread()) {
53 summary->thread()->Destroy();
54 }
55 }
56
Destroy()57 void AsanThread::Destroy() {
58 if (flags()->verbosity >= 1) {
59 Report("T%d exited\n", tid());
60 }
61
62 asanThreadRegistry().UnregisterThread(this);
63 CHECK(summary()->thread() == 0);
64 // We also clear the shadow on thread destruction because
65 // some code may still be executing in later TSD destructors
66 // and we don't want it to have any poisoned stack.
67 ClearShadowForThreadStack();
68 fake_stack().Cleanup();
69 uptr size = RoundUpTo(sizeof(AsanThread), kPageSize);
70 UnmapOrDie(this, size);
71 }
72
Init()73 void AsanThread::Init() {
74 SetThreadStackTopAndBottom();
75 CHECK(AddrIsInMem(stack_bottom_));
76 CHECK(AddrIsInMem(stack_top_));
77 ClearShadowForThreadStack();
78 if (flags()->verbosity >= 1) {
79 int local = 0;
80 Report("T%d: stack [%p,%p) size 0x%zx; local=%p\n",
81 tid(), (void*)stack_bottom_, (void*)stack_top_,
82 stack_top_ - stack_bottom_, &local);
83 }
84 fake_stack_.Init(stack_size());
85 AsanPlatformThreadInit();
86 }
87
ThreadStart()88 thread_return_t AsanThread::ThreadStart() {
89 Init();
90 if (flags()->use_sigaltstack) SetAlternateSignalStack();
91
92 if (!start_routine_) {
93 // start_routine_ == 0 if we're on the main thread or on one of the
94 // OS X libdispatch worker threads. But nobody is supposed to call
95 // ThreadStart() for the worker threads.
96 CHECK(tid() == 0);
97 return 0;
98 }
99
100 thread_return_t res = start_routine_(arg_);
101 malloc_storage().CommitBack();
102 if (flags()->use_sigaltstack) UnsetAlternateSignalStack();
103
104 this->Destroy();
105
106 return res;
107 }
108
SetThreadStackTopAndBottom()109 void AsanThread::SetThreadStackTopAndBottom() {
110 GetThreadStackTopAndBottom(tid() == 0, &stack_top_, &stack_bottom_);
111 int local;
112 CHECK(AddrIsInStack((uptr)&local));
113 }
114
ClearShadowForThreadStack()115 void AsanThread::ClearShadowForThreadStack() {
116 PoisonShadow(stack_bottom_, stack_top_ - stack_bottom_, 0);
117 }
118
GetFrameNameByAddr(uptr addr,uptr * offset)119 const char *AsanThread::GetFrameNameByAddr(uptr addr, uptr *offset) {
120 uptr bottom = 0;
121 bool is_fake_stack = false;
122 if (AddrIsInStack(addr)) {
123 bottom = stack_bottom();
124 } else {
125 bottom = fake_stack().AddrIsInFakeStack(addr);
126 CHECK(bottom);
127 is_fake_stack = true;
128 }
129 uptr aligned_addr = addr & ~(__WORDSIZE/8 - 1); // align addr.
130 u8 *shadow_ptr = (u8*)MemToShadow(aligned_addr);
131 u8 *shadow_bottom = (u8*)MemToShadow(bottom);
132
133 while (shadow_ptr >= shadow_bottom &&
134 *shadow_ptr != kAsanStackLeftRedzoneMagic) {
135 shadow_ptr--;
136 }
137
138 while (shadow_ptr >= shadow_bottom &&
139 *shadow_ptr == kAsanStackLeftRedzoneMagic) {
140 shadow_ptr--;
141 }
142
143 if (shadow_ptr < shadow_bottom) {
144 *offset = 0;
145 return "UNKNOWN";
146 }
147
148 uptr* ptr = (uptr*)SHADOW_TO_MEM((uptr)(shadow_ptr + 1));
149 CHECK((ptr[0] == kCurrentStackFrameMagic) ||
150 (is_fake_stack && ptr[0] == kRetiredStackFrameMagic));
151 *offset = addr - (uptr)ptr;
152 return (const char*)ptr[1];
153 }
154
155 } // namespace __asan
156