Merge "Add a logging handler on timeout."
diff --git a/libbacktrace/BacktraceCurrent.cpp b/libbacktrace/BacktraceCurrent.cpp
index 2714d93..d339550 100644
--- a/libbacktrace/BacktraceCurrent.cpp
+++ b/libbacktrace/BacktraceCurrent.cpp
@@ -93,6 +93,10 @@
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 @@
// 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;