diff --git a/lldb/include/lldb/Host/OptionParser.h b/lldb/include/lldb/Host/OptionParser.h
index 5aa7db5d34bf..175a1973c7af 100644
--- a/lldb/include/lldb/Host/OptionParser.h
+++ b/lldb/include/lldb/Host/OptionParser.h
@@ -11,6 +11,7 @@
 #define liblldb_OptionParser_h_
 
 #include <string>
+#include "lldb/Host/Mutex.h"
 
 struct option;
 
@@ -38,7 +39,7 @@ public:
         eOptionalArgument
     };
 
-    static void Prepare();
+    static void Prepare(Mutex::Locker &locker);
 
     static void EnableError(bool error);
 
diff --git a/lldb/source/Host/common/OptionParser.cpp b/lldb/source/Host/common/OptionParser.cpp
index a91e764bfe3b..a9784592a738 100644
--- a/lldb/source/Host/common/OptionParser.cpp
+++ b/lldb/source/Host/common/OptionParser.cpp
@@ -16,8 +16,10 @@
 using namespace lldb_private;
 
 void
-OptionParser::Prepare()
+OptionParser::Prepare(Mutex::Locker &locker)
 {
+    static Mutex g_mutex(Mutex::eMutexTypeNormal);
+    locker.Lock(g_mutex);
 #ifdef __GLIBC__
     optind = 0;
 #else
diff --git a/lldb/source/Interpreter/Args.cpp b/lldb/source/Interpreter/Args.cpp
index 7c9f5c35ecb7..81e6b0aa1dbc 100644
--- a/lldb/source/Interpreter/Args.cpp
+++ b/lldb/source/Interpreter/Args.cpp
@@ -575,7 +575,8 @@ Args::ParseOptions (Options &options)
             }
         }
     }
-    OptionParser::Prepare();
+    Mutex::Locker options_locker(NULL);
+    OptionParser::Prepare(options_locker);
     int val;
     while (1)
     {
@@ -1189,7 +1190,8 @@ Args::ParseAliasOptions (Options &options,
         }
     }
 
-    OptionParser::Prepare();
+    Mutex::Locker options_locker(NULL);
+    OptionParser::Prepare(options_locker);
     int val;
     while (1)
     {
@@ -1366,7 +1368,8 @@ Args::ParseArgsForCompletion
         }
     }
 
-    OptionParser::Prepare();
+    Mutex::Locker options_locker(NULL);
+    OptionParser::Prepare(options_locker);
     OptionParser::EnableError(false);
 
     int val;