1
2 #include "msan.h"
3 #include "msan_thread.h"
4 #include "msan_interface_internal.h"
5
6 #include "sanitizer_common/sanitizer_tls_get_addr.h"
7
8 namespace __msan {
9
Create(thread_callback_t start_routine,void * arg)10 MsanThread *MsanThread::Create(thread_callback_t start_routine,
11 void *arg) {
12 uptr PageSize = GetPageSizeCached();
13 uptr size = RoundUpTo(sizeof(MsanThread), PageSize);
14 MsanThread *thread = (MsanThread*)MmapOrDie(size, __func__);
15 thread->start_routine_ = start_routine;
16 thread->arg_ = arg;
17 thread->destructor_iterations_ = GetPthreadDestructorIterations();
18
19 return thread;
20 }
21
SetThreadStackAndTls()22 void MsanThread::SetThreadStackAndTls() {
23 uptr tls_size = 0;
24 uptr stack_size = 0;
25 GetThreadStackAndTls(IsMainThread(), &stack_.bottom, &stack_size, &tls_begin_,
26 &tls_size);
27 stack_.top = stack_.bottom + stack_size;
28 tls_end_ = tls_begin_ + tls_size;
29
30 int local;
31 CHECK(AddrIsInStack((uptr)&local));
32 }
33
ClearShadowForThreadStackAndTLS()34 void MsanThread::ClearShadowForThreadStackAndTLS() {
35 __msan_unpoison((void *)stack_.bottom, stack_.top - stack_.bottom);
36 if (tls_begin_ != tls_end_)
37 __msan_unpoison((void *)tls_begin_, tls_end_ - tls_begin_);
38 DTLS *dtls = DTLS_Get();
39 CHECK_NE(dtls, 0);
40 ForEachDVT(dtls, [](const DTLS::DTV &dtv, int id) {
41 __msan_unpoison((void *)(dtv.beg), dtv.size);
42 });
43 }
44
Init()45 void MsanThread::Init() {
46 SetThreadStackAndTls();
47 CHECK(MEM_IS_APP(stack_.bottom));
48 CHECK(MEM_IS_APP(stack_.top - 1));
49 ClearShadowForThreadStackAndTLS();
50 malloc_storage().Init();
51 }
52
TSDDtor(void * tsd)53 void MsanThread::TSDDtor(void *tsd) {
54 MsanThread *t = (MsanThread*)tsd;
55 t->Destroy();
56 }
57
Destroy()58 void MsanThread::Destroy() {
59 malloc_storage().CommitBack();
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 ClearShadowForThreadStackAndTLS();
64 uptr size = RoundUpTo(sizeof(MsanThread), GetPageSizeCached());
65 UnmapOrDie(this, size);
66 DTLS_Destroy();
67 }
68
ThreadStart()69 thread_return_t MsanThread::ThreadStart() {
70 if (!start_routine_) {
71 // start_routine_ == 0 if we're on the main thread or on one of the
72 // OS X libdispatch worker threads. But nobody is supposed to call
73 // ThreadStart() for the worker threads.
74 return 0;
75 }
76
77 thread_return_t res = start_routine_(arg_);
78
79 return res;
80 }
81
GetStackBounds() const82 MsanThread::StackBounds MsanThread::GetStackBounds() const {
83 if (!stack_switching_)
84 return {stack_.bottom, stack_.top};
85 const uptr cur_stack = GET_CURRENT_FRAME();
86 // Note: need to check next stack first, because FinishSwitchFiber
87 // may be in process of overwriting stack_.top/bottom_. But in such case
88 // we are already on the next stack.
89 if (cur_stack >= next_stack_.bottom && cur_stack < next_stack_.top)
90 return {next_stack_.bottom, next_stack_.top};
91 return {stack_.bottom, stack_.top};
92 }
93
stack_top()94 uptr MsanThread::stack_top() { return GetStackBounds().top; }
95
stack_bottom()96 uptr MsanThread::stack_bottom() { return GetStackBounds().bottom; }
97
AddrIsInStack(uptr addr)98 bool MsanThread::AddrIsInStack(uptr addr) {
99 const auto bounds = GetStackBounds();
100 return addr >= bounds.bottom && addr < bounds.top;
101 }
102
StartSwitchFiber(uptr bottom,uptr size)103 void MsanThread::StartSwitchFiber(uptr bottom, uptr size) {
104 CHECK(!stack_switching_);
105 next_stack_.bottom = bottom;
106 next_stack_.top = bottom + size;
107 stack_switching_ = true;
108 }
109
FinishSwitchFiber(uptr * bottom_old,uptr * size_old)110 void MsanThread::FinishSwitchFiber(uptr *bottom_old, uptr *size_old) {
111 CHECK(stack_switching_);
112 if (bottom_old)
113 *bottom_old = stack_.bottom;
114 if (size_old)
115 *size_old = stack_.top - stack_.bottom;
116 stack_.bottom = next_stack_.bottom;
117 stack_.top = next_stack_.top;
118 stack_switching_ = false;
119 next_stack_.top = 0;
120 next_stack_.bottom = 0;
121 }
122
123 } // namespace __msan
124