From 8934213a6a780fcdafc2ce64bce8410e268baa88 Mon Sep 17 00:00:00 2001
From: Alja Mrak-Tadel <amraktadel@ucsd.edu>
Date: Wed, 17 Aug 2016 13:54:12 -0700
Subject: [PATCH] Protect against spurious wakeups in SyncResponseHandler.

---
 src/XrdCl/XrdClMessageUtils.hh | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/XrdCl/XrdClMessageUtils.hh b/src/XrdCl/XrdClMessageUtils.hh
index f71bdad5174..34be84b4f64 100644
--- a/src/XrdCl/XrdClMessageUtils.hh
+++ b/src/XrdCl/XrdClMessageUtils.hh
@@ -44,14 +44,13 @@ namespace XrdCl
       SyncResponseHandler():
         pStatus(0),
         pResponse(0),
-        pSem( new Semaphore(0) ) {}
+        pCondVar(0) {}
 
       //------------------------------------------------------------------------
       //! Destructor
       //------------------------------------------------------------------------
       virtual ~SyncResponseHandler()
       {
-        delete pSem;
       }
 
 
@@ -61,9 +60,10 @@ namespace XrdCl
       virtual void HandleResponse( XRootDStatus *status,
                                    AnyObject    *response )
       {
+        XrdSysCondVarHelper scopedLock(pCondVar);
         pStatus = status;
         pResponse = response;
-        pSem->Post();
+        pCondVar.Broadcast();
       }
 
       //------------------------------------------------------------------------
@@ -87,7 +87,10 @@ namespace XrdCl
       //------------------------------------------------------------------------
       void WaitForResponse()
       {
-        pSem->Wait();
+        XrdSysCondVarHelper scopedLock(pCondVar);
+        while (pStatus == 0) {
+          pCondVar.Wait();
+        }
       }
 
     private:
@@ -96,9 +99,10 @@ namespace XrdCl
 
       XRootDStatus    *pStatus;
       AnyObject       *pResponse;
-      Semaphore       *pSem;
+      XrdSysCondVar    pCondVar;
   };
 
+
   //----------------------------------------------------------------------------
   // We're not interested in the response just commit suicide
   //----------------------------------------------------------------------------