diff --git a/lldb/source/Core/Communication.cpp b/lldb/source/Core/Communication.cpp
--- a/lldb/source/Core/Communication.cpp
+++ b/lldb/source/Core/Communication.cpp
@@ -315,14 +315,14 @@
   Status error;
   ConnectionStatus status = eConnectionStatusSuccess;
   bool done = false;
+  bool disconnect = false;
   while (!done && comm->m_read_thread_enabled) {
     size_t bytes_read = comm->ReadFromConnection(
         buf, sizeof(buf), std::chrono::seconds(5), status, &error);
     if (bytes_read > 0)
       comm->AppendBytesToCache(buf, bytes_read, true, status);
     else if ((bytes_read == 0) && status == eConnectionStatusEndOfFile) {
-      if (comm->GetCloseOnEOF())
-        comm->Disconnect();
+      disconnect = comm->GetCloseOnEOF();
       comm->AppendBytesToCache(buf, bytes_read, true, status);
     }
 
@@ -336,7 +336,7 @@
     case eConnectionStatusError: // Check GetError() for details
       if (error.GetType() == eErrorTypePOSIX && error.GetError() == EIO) {
         // EIO on a pipe is usually caused by remote shutdown
-        comm->Disconnect();
+        disconnect = comm->GetCloseOnEOF();
         done = true;
       }
       if (error.Fail())
@@ -365,9 +365,15 @@
   if (log)
     LLDB_LOGF(log, "%p Communication::ReadThread () thread exiting...", p);
 
-  comm->m_read_thread_did_exit = true;
-  // Let clients know that this thread is exiting
   comm->BroadcastEvent(eBroadcastBitNoMorePendingInput);
+  {
+    std::lock_guard<std::mutex> guard(comm->m_synchronize_mutex);
+    comm->m_read_thread_did_exit = true;
+    if (disconnect)
+      comm->Disconnect();
+  }
+
+  // Let clients know that this thread is exiting
   comm->BroadcastEvent(eBroadcastBitReadThreadDidExit);
   return {};
 }
diff --git a/lldb/unittests/Core/CMakeLists.txt b/lldb/unittests/Core/CMakeLists.txt
--- a/lldb/unittests/Core/CMakeLists.txt
+++ b/lldb/unittests/Core/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_lldb_unittest(LLDBCoreTests
+  CommunicationTest.cpp
   MangledTest.cpp
   RichManglingContextTest.cpp
   StreamCallbackTest.cpp
diff --git a/lldb/unittests/Core/CommunicationTest.cpp b/lldb/unittests/Core/CommunicationTest.cpp
new file mode 100644
--- /dev/null
+++ b/lldb/unittests/Core/CommunicationTest.cpp
@@ -0,0 +1,36 @@
+//===-- CommunicationTest.cpp ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Core/Communication.h"
+#include "lldb/Host/ConnectionFileDescriptor.h"
+#include "lldb/Host/Pipe.h"
+#include "llvm/Testing/Support/Error.h"
+#include "gtest/gtest.h"
+
+using namespace lldb_private;
+
+TEST(CommunicationTest, SynchronizeWhileClosing) {
+  // Set up a communication object reading from a pipe.
+  Pipe pipe;
+  ASSERT_THAT_ERROR(pipe.CreateNew(/*child_process_inherit=*/false).ToError(),
+                    llvm::Succeeded());
+  auto conn_up = std::make_unique<ConnectionFileDescriptor>(
+      pipe.ReleaseReadFileDescriptor(), /*owns_fd=*/true);
+
+  Communication comm("test");
+  comm.SetConnection(conn_up.release());
+  comm.SetCloseOnEOF(true);
+  ASSERT_TRUE(comm.StartReadThread());
+
+  // Ensure that we can safely synchronize with the read thread while it is
+  // closing the read end (in response to us closing the write end).
+  pipe.CloseWriteFileDescriptor();
+  comm.SynchronizeWithReadThread();
+
+  ASSERT_TRUE(comm.StopReadThread());
+}