Merge "Add a logging handler on timeout." (825477ff) · Commits · e / os / android_system_core

libbacktrace/BacktraceCurrent.cpp

+17 −1

Original line number	Diff line number	Diff line
		@@ -93,6 +93,10 @@ bool BacktraceCurrent::DiscardFrame(const backtrace_frame_data_t& frame) {

		static pthread_mutex_t g_sigaction_mutex = PTHREAD_MUTEX_INITIALIZER;

		static void SignalLogOnly(int, siginfo_t, void) {
		BACK_LOGE("pid %d, tid %d: Received a spurious signal %d\n", getpid(), gettid(), THREAD_SIGNAL);
		}

		static void SignalHandler(int, siginfo_t, void sigcontext) {
		ThreadEntry* entry = ThreadEntry::Get(getpid(), gettid(), false);
		if (!entry) {
		@@ -151,9 +155,21 @@ bool BacktraceCurrent::UnwindThread(size_t num_ignore_frames) {
		// that we are waiting for the first Wake() call made by the thread.
		bool wait_completed = entry->Wait(1);

		if (!wait_completed && oldact.sa_sigaction == nullptr) {
		// If the wait failed, it could be that the signal could not be delivered
		// within the timeout. Add a signal handler that's simply going to log
		// something so that we don't crash if the signal eventually gets
		// delivered. Only do this if there isn't already an action set up.
		memset(&act, 0, sizeof(act));
		act.sa_sigaction = SignalLogOnly;
		act.sa_flags = SA_RESTART \| SA_SIGINFO \| SA_ONSTACK;
		sigemptyset(&act.sa_mask);
		sigaction(THREAD_SIGNAL, &act, nullptr);
		} else {
		sigaction(THREAD_SIGNAL, &oldact, nullptr);
		}
		// After the thread has received the signal, allow other unwinders to
		// continue.
		sigaction(THREAD_SIGNAL, &oldact, nullptr);
		pthread_mutex_unlock(&g_sigaction_mutex);

		bool unwind_done = false;