tsan: stop background thread when sandbox is enabled

Fixes https://code.google.com/p/thread-sanitizer/issues/detail?id=56



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@207114 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 33 insertions, 7 deletions

diff --git a/lib/tsan/rtl/tsan_interceptors.cc b/lib/tsan/rtl/tsan_interceptors.cc
index b9f02b9d9..b545f8c52 100644
--- a/lib/tsan/rtl/tsan_interceptors.cc
+++ b/lib/tsan/rtl/tsan_interceptors.cc
@@ -2473,15 +2473,19 @@ void InitializeInterceptors() {
   FdInit();
 }
 
-void internal_start_thread(void(*func)(void *arg), void *arg) {
+void *internal_start_thread(void(*func)(void *arg), void *arg) {
   // Start the thread with signals blocked, otherwise it can steal user signals.
   __sanitizer_sigset_t set, old;
   internal_sigfillset(&set);
   internal_sigprocmask(SIG_SETMASK, &set, &old);
   void *th;
   REAL(pthread_create)(&th, 0, (void*(*)(void *arg))func, arg);
-  REAL(pthread_detach)(th);
   internal_sigprocmask(SIG_SETMASK, &old, 0);
+  return th;
+}
+
+void internal_join_thread(void *th) {
+  REAL(pthread_join)(th, 0);
 }
 
 }  // namespace __tsan
diff --git a/lib/tsan/rtl/tsan_platform.h b/lib/tsan/rtl/tsan_platform.h
index e960d5d99..7abe5f0d7 100644
--- a/lib/tsan/rtl/tsan_platform.h
+++ b/lib/tsan/rtl/tsan_platform.h
@@ -164,7 +164,8 @@ uptr ALWAYS_INLINE GetThreadTraceHeader(int tid) {
   return p;
 }
 
-void internal_start_thread(void(*func)(void*), void *arg);
+void *internal_start_thread(void(*func)(void*), void *arg);
+void internal_join_thread(void *th);
 
 // Says whether the addr relates to a global var.
 // Guesses with high probability, may yield both false positives and negatives.
diff --git a/lib/tsan/rtl/tsan_rtl.cc b/lib/tsan/rtl/tsan_rtl.cc
index b0ae2dd59..33b9f0bc2 100644
--- a/lib/tsan/rtl/tsan_rtl.cc
+++ b/lib/tsan/rtl/tsan_rtl.cc
@@ -120,8 +120,13 @@ static void MemoryProfiler(Context *ctx, fd_t fd, int i) {
 }
 
 static void BackgroundThread(void *arg) {
+#ifndef TSAN_GO
   // This is a non-initialized non-user thread, nothing to see here.
-  ScopedIgnoreInterceptors ignore;
+  // We don't use ScopedIgnoreInterceptors, because we want ignores to be
+  // enabled even when the thread function exits (e.g. during pthread thread
+  // shutdown code).
+  cur_thread()->ignore_interceptors++;
+#endif
   const u64 kMs2Ns = 1000 * 1000;
 
   fd_t mprof_fd = kInvalidFd;
@@ -140,8 +145,10 @@ static void BackgroundThread(void *arg) {
 
   u64 last_flush = NanoTime();
   uptr last_rss = 0;
-  for (int i = 0; ; i++) {
-    SleepForSeconds(1);
+  for (int i = 0;
+      atomic_load(&ctx->stop_background_thread, memory_order_relaxed) == 0;
+      i++) {
+    SleepForMillis(100);
     u64 now = NanoTime();
 
     // Flush memory if requested.
@@ -192,6 +199,16 @@ static void BackgroundThread(void *arg) {
   }
 }
 
+static void StartBackgroundThread() {
+  ctx->background_thread = internal_start_thread(&BackgroundThread, 0);
+}
+
+static void StopBackgroundThread() {
+  atomic_store(&ctx->stop_background_thread, 1, memory_order_relaxed);
+  internal_join_thread(ctx->background_thread);
+  ctx->background_thread = 0;
+}
+
 void DontNeedShadowFor(uptr addr, uptr size) {
   uptr shadow_beg = MemToShadow(addr);
   uptr shadow_end = MemToShadow(addr + size);
@@ -250,7 +267,8 @@ void Initialize(ThreadState *thr) {
   Symbolizer::Init(common_flags()->external_symbolizer_path);
   Symbolizer::Get()->AddHooks(EnterSymbolizer, ExitSymbolizer);
 #endif
-  internal_start_thread(&BackgroundThread, 0);
+  StartBackgroundThread();
+  SetSandboxingCallback(StopBackgroundThread);
   if (flags()->detect_deadlocks)
     ctx->dd = DDetector::Create(flags());
 
diff --git a/lib/tsan/rtl/tsan_rtl.h b/lib/tsan/rtl/tsan_rtl.h
index f862e5213..c542bd2bc 100644
--- a/lib/tsan/rtl/tsan_rtl.h
+++ b/lib/tsan/rtl/tsan_rtl.h
@@ -536,6 +536,9 @@ struct Context {
   int nmissed_expected;
   atomic_uint64_t last_symbolize_time_ns;
 
+  void *background_thread;
+  atomic_uint32_t stop_background_thread;
+
   ThreadRegistry *thread_registry;
 
   Vector<RacyStacks> racy_stacks;