From fa1e6a1836ef7b6a7c3b05911cfb9f5b3da7eefc Mon Sep 17 00:00:00 2001
From: Jonathan Lifflander <jliffla@sandia.gov>
Date: Thu, 17 Sep 2020 18:26:01 -0700
Subject: [PATCH] #1014: runtime: check MPI_Comm for use during component
 startup

---
 src/vt/runtime/runtime.cc | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/vt/runtime/runtime.cc b/src/vt/runtime/runtime.cc
index 5355ccaec2..bef793d8c3 100644
--- a/src/vt/runtime/runtime.cc
+++ b/src/vt/runtime/runtime.cc
@@ -456,7 +456,15 @@ bool Runtime::finalize(bool const force_now, bool const disable_sig) {
 }
 
 void Runtime::sync() {
-  MPI_Barrier(communicator_);
+  MPI_Comm comm = communicator_;
+  if (comm == MPI_COMM_NULL and theContext != nullptr) {
+    comm = theContext->getComm();
+  }
+  if (comm == MPI_COMM_NULL) {
+    vtAbort("Trying to sync runtime while the communicator is not available");
+  } else {
+    MPI_Barrier(comm);
+  }
 }
 
 void Runtime::runScheduler() {