diff --git a/storage/ndb/src/mgmsrv/MgmtSrvr.cpp b/storage/ndb/src/mgmsrv/MgmtSrvr.cpp
index aee6d4deeb5..1e655c29517 100644
--- a/storage/ndb/src/mgmsrv/MgmtSrvr.cpp
+++ b/storage/ndb/src/mgmsrv/MgmtSrvr.cpp
@@ -2514,6 +2514,7 @@ int
 MgmtSrvr::abortBackup(Uint32 backupId)
 {
   SignalSender ss(theFacade);
+  ss.lock(); // lock will be released on exit
 
   bool next;
   NodeId nodeId = 0;
diff --git a/storage/ndb/src/ndbapi/SignalSender.cpp b/storage/ndb/src/ndbapi/SignalSender.cpp
index a29fe68937b..0ecc98f5f29 100644
--- a/storage/ndb/src/ndbapi/SignalSender.cpp
+++ b/storage/ndb/src/ndbapi/SignalSender.cpp
@@ -75,7 +75,9 @@ SignalSender::SignalSender(TransporterFacade *facade)
 {
   m_cond = NdbCondition_Create();
   theFacade = facade;
+  lock();
   m_blockNo = theFacade->open(this, execSignal, execNodeStatus);
+  unlock();
   assert(m_blockNo > 0);
 }