From: Peter Munch <peterrmuench@gmail.com>
Date: Mon, 31 May 2021 11:35:55 +0000 (+0200)
Subject: RemotePointEvaluation: fix race condition if called multiple times
X-Git-Tag: v9.3.0~4^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=16c4b8f0a81ed66f1c9334de1facac9acd88aba4;p=dealii.git

RemotePointEvaluation: fix race condition if called multiple times
---

diff --git a/include/deal.II/base/mpi_remote_point_evaluation.h b/include/deal.II/base/mpi_remote_point_evaluation.h
index ebd3f3a5b8..182b779d5a 100644
--- a/include/deal.II/base/mpi_remote_point_evaluation.h
+++ b/include/deal.II/base/mpi_remote_point_evaluation.h
@@ -266,6 +266,9 @@ namespace Utilities
       (void)buffer;
       (void)evaluation_function;
 #else
+      static CollectiveMutex      mutex;
+      CollectiveMutex::ScopedLock lock(mutex, tria->get_communicator());
+
       output.resize(point_ptrs.back());
       buffer.resize(send_permutation.size() * 2);
       ArrayView<T> buffer_1(buffer.data(), buffer.size() / 2);
@@ -377,6 +380,9 @@ namespace Utilities
       (void)buffer;
       (void)evaluation_function;
 #else
+      static CollectiveMutex      mutex;
+      CollectiveMutex::ScopedLock lock(mutex, tria->get_communicator());
+
       const auto &ptr = this->get_point_ptrs();
 
       std::map<unsigned int, std::vector<T>> temp_recv_map;