Guard against re-entrant requests for stack traces.

runtime/vm/profiler.cc

Index: runtime/vm/profiler.cc
diff --git a/runtime/vm/profiler.cc b/runtime/vm/profiler.cc
index b8827c58e7f1109068c6035ea041db8114e01ae2..ab1d2ebc4d7da14828302568bc484265d4adf240 100644
--- a/runtime/vm/profiler.cc
+++ b/runtime/vm/profiler.cc
@@ -948,6 +948,15 @@ static uintptr_t __attribute__((noinline)) GetProgramCounter() {
 
 
 void Profiler::DumpStackTrace(bool native_stack_trace) {
+  // Allow only one stack trace to prevent recursively printing stack traces if
+  // we hit an assert while printing the stack.
+  static bool started_dump = false;

[zra, 2016/08/10 17:52:27]

It probably doesn't matter that this is not thread safe, but maybe it would
forestall some extra prints if this was a FetchAndIncrement and then a check.

[rmacnak, 2016/08/11 00:08:02]

Done.

+  if (started_dump) {
+    OS::PrintErr("Aborting re-entrant request for stack trace.\n");
+    return;
+  }
+  started_dump = true;
+
   Thread* thread = Thread::Current();
   if (thread == NULL) {
     return;