1d3ef5f122
Add functions exposed via the MSAN interface to enable MSAN within binaries that perform manual stack switching (e.g. through using fibers or coroutines). This functionality is analogous to the fiber APIs available for ASAN and TSAN. Fixes google/sanitizers#1232 Reviewed By: vitalybuka Differential Revision: https://reviews.llvm.org/D86471
124 lines
3.6 KiB
C++
124 lines
3.6 KiB
C++
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#include "msan.h"
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#include "msan_thread.h"
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#include "msan_interface_internal.h"
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#include "sanitizer_common/sanitizer_tls_get_addr.h"
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namespace __msan {
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MsanThread *MsanThread::Create(thread_callback_t start_routine,
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void *arg) {
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uptr PageSize = GetPageSizeCached();
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uptr size = RoundUpTo(sizeof(MsanThread), PageSize);
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MsanThread *thread = (MsanThread*)MmapOrDie(size, __func__);
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thread->start_routine_ = start_routine;
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thread->arg_ = arg;
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thread->destructor_iterations_ = GetPthreadDestructorIterations();
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return thread;
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}
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void MsanThread::SetThreadStackAndTls() {
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uptr tls_size = 0;
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uptr stack_size = 0;
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GetThreadStackAndTls(IsMainThread(), &stack_.bottom, &stack_size, &tls_begin_,
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&tls_size);
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stack_.top = stack_.bottom + stack_size;
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tls_end_ = tls_begin_ + tls_size;
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int local;
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CHECK(AddrIsInStack((uptr)&local));
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}
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void MsanThread::ClearShadowForThreadStackAndTLS() {
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__msan_unpoison((void *)stack_.bottom, stack_.top - stack_.bottom);
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if (tls_begin_ != tls_end_)
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__msan_unpoison((void *)tls_begin_, tls_end_ - tls_begin_);
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DTLS *dtls = DTLS_Get();
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CHECK_NE(dtls, 0);
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for (uptr i = 0; i < dtls->dtv_size; ++i)
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__msan_unpoison((void *)(dtls->dtv[i].beg), dtls->dtv[i].size);
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}
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void MsanThread::Init() {
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SetThreadStackAndTls();
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CHECK(MEM_IS_APP(stack_.bottom));
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CHECK(MEM_IS_APP(stack_.top - 1));
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ClearShadowForThreadStackAndTLS();
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}
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void MsanThread::TSDDtor(void *tsd) {
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MsanThread *t = (MsanThread*)tsd;
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t->Destroy();
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}
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void MsanThread::Destroy() {
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malloc_storage().CommitBack();
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// We also clear the shadow on thread destruction because
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// some code may still be executing in later TSD destructors
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// and we don't want it to have any poisoned stack.
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ClearShadowForThreadStackAndTLS();
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uptr size = RoundUpTo(sizeof(MsanThread), GetPageSizeCached());
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UnmapOrDie(this, size);
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DTLS_Destroy();
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}
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thread_return_t MsanThread::ThreadStart() {
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Init();
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if (!start_routine_) {
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// start_routine_ == 0 if we're on the main thread or on one of the
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// OS X libdispatch worker threads. But nobody is supposed to call
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// ThreadStart() for the worker threads.
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return 0;
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}
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thread_return_t res = start_routine_(arg_);
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return res;
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}
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MsanThread::StackBounds MsanThread::GetStackBounds() const {
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if (!stack_switching_)
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return {stack_.bottom, stack_.top};
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const uptr cur_stack = GET_CURRENT_FRAME();
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// Note: need to check next stack first, because FinishSwitchFiber
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// may be in process of overwriting stack_.top/bottom_. But in such case
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// we are already on the next stack.
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if (cur_stack >= next_stack_.bottom && cur_stack < next_stack_.top)
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return {next_stack_.bottom, next_stack_.top};
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return {stack_.bottom, stack_.top};
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}
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uptr MsanThread::stack_top() { return GetStackBounds().top; }
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uptr MsanThread::stack_bottom() { return GetStackBounds().bottom; }
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bool MsanThread::AddrIsInStack(uptr addr) {
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const auto bounds = GetStackBounds();
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return addr >= bounds.bottom && addr < bounds.top;
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}
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void MsanThread::StartSwitchFiber(uptr bottom, uptr size) {
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CHECK(!stack_switching_);
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next_stack_.bottom = bottom;
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next_stack_.top = bottom + size;
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stack_switching_ = true;
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}
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void MsanThread::FinishSwitchFiber(uptr *bottom_old, uptr *size_old) {
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CHECK(stack_switching_);
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if (bottom_old)
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*bottom_old = stack_.bottom;
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if (size_old)
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*size_old = stack_.top - stack_.bottom;
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stack_.bottom = next_stack_.bottom;
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stack_.top = next_stack_.top;
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stack_switching_ = false;
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next_stack_.top = 0;
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next_stack_.bottom = 0;
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}
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} // namespace __msan
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