diff --git a/lldb/source/Host/common/NativeProcessProtocol.cpp b/lldb/source/Host/common/NativeProcessProtocol.cpp
index b7a7726..e192f19 100644
--- a/lldb/source/Host/common/NativeProcessProtocol.cpp
+++ b/lldb/source/Host/common/NativeProcessProtocol.cpp
@@ -13,6 +13,7 @@
 #include "lldb/Core/ArchSpec.h"
 #include "lldb/Core/Log.h"
 #include "lldb/Core/State.h"
+#include "lldb/Host/Host.h"
 #include "lldb/Target/NativeRegisterContext.h"
 
 #include "NativeThreadProtocol.h"
@@ -44,6 +45,18 @@
 }
 
 lldb_private::Error
+NativeProcessProtocol::Interrupt ()
+{
+    Error error;
+#if !defined (SIGSTOP)
+    error.SetErrorString ("local host does not support signaling");
+    return error;
+#else
+    return Signal (SIGSTOP);
+#endif
+}
+
+lldb_private::Error
 NativeProcessProtocol::GetMemoryRegionInfo (lldb::addr_t load_addr, MemoryRegionInfo &range_info)
 {
     // Default: not implemented.
@@ -110,9 +123,8 @@
 }
 
 NativeThreadProtocolSP
-NativeProcessProtocol::GetThreadByID (lldb::tid_t tid)
+NativeProcessProtocol::GetThreadByIDUnlocked (lldb::tid_t tid)
 {
-    Mutex::Locker locker (m_threads_mutex);
     for (auto thread_sp : m_threads)
     {
         if (thread_sp->GetID() == tid)
@@ -121,6 +133,13 @@
     return NativeThreadProtocolSP ();
 }
 
+NativeThreadProtocolSP
+NativeProcessProtocol::GetThreadByID (lldb::tid_t tid)
+{
+    Mutex::Locker locker (m_threads_mutex);
+    return GetThreadByIDUnlocked (tid);
+}
+
 bool
 NativeProcessProtocol::IsAlive () const
 {