diff --git a/src/allreduce_base.cc b/src/allreduce_base.cc
index 6ef941425..f90e5d621 100644
--- a/src/allreduce_base.cc
+++ b/src/allreduce_base.cc
@@ -55,7 +55,8 @@ void AllreduceBase::Shutdown(void) {
 
   utils::Assert(master.SendAll(&rank, sizeof(rank)) == sizeof(rank), "ReConnectLink failure 3");
   master.SendStr(job_id);
-  master.SendStr(std::string("shutdown"));
+  master.SendStr(std::string("shutdown"));  
+  master.Close();
   utils::TCPSocket::Finalize();
 }
 /*!
@@ -102,7 +103,6 @@ void AllreduceBase::ReConnectLinks(void) {
   utils::Assert(master.SendAll(&magic, sizeof(magic)) == sizeof(magic), "ReConnectLink failure 1");
   utils::Assert(master.RecvAll(&magic, sizeof(magic)) == sizeof(magic), "ReConnectLink failure 2");
   utils::Check(magic == kMagic, "sync::Invalid master message, init failure");
-
   utils::Assert(master.SendAll(&rank, sizeof(rank)) == sizeof(rank), "ReConnectLink failure 3");
   master.SendStr(job_id);
   master.SendStr(std::string("start"));
@@ -112,10 +112,11 @@ void AllreduceBase::ReConnectLinks(void) {
                   "ReConnectLink failure 4");
     utils::Assert(master.RecvAll(&parent_rank, sizeof(parent_rank)) == sizeof(parent_rank),
                   "ReConnectLink failure 4");
+    utils::Assert(master.RecvAll(&world_size, sizeof(world_size)) == sizeof(world_size),
+                  "ReConnectLink failure 4");
     utils::Assert(rank == -1 || newrank == rank, "must keep rank to same if the node already have one");
     rank = newrank;    
-  }
-  
+  }  
   // create listening socket
   utils::TCPSocket sock_listen;
   sock_listen.Create();
@@ -125,7 +126,6 @@ void AllreduceBase::ReConnectLinks(void) {
 
   // get number of to connect and number of to accept nodes from master
   int num_conn, num_accept, num_error = 1;
-
   do {
     // send over good links
     std::vector<int> good_link;
@@ -146,7 +146,7 @@ void AllreduceBase::ReConnectLinks(void) {
     utils::Assert(master.RecvAll(&num_conn, sizeof(num_conn)) == sizeof(num_conn),
                   "ReConnectLink failure 7");
     utils::Assert(master.RecvAll(&num_accept, sizeof(num_accept)) == sizeof(num_accept),
-                  "ReConnectLink failure 8");
+                  "ReConnectLink failure 8");    
     num_error = 0;
     for (int i = 0; i < num_conn; ++i) {
       LinkRecord r;
@@ -202,7 +202,6 @@ void AllreduceBase::ReConnectLinks(void) {
     links[i].sock.SetNonBlock(true);
     if (links[i].rank == parent_rank) parent_index = static_cast<int>(i);
   }
-  utils::LogPrintf("[%d] parent_rank=%d, parent_index=%d, nlink=%d\n", rank, parent_rank, parent_index, (int)links.size());
   if (parent_rank != -1) {
     utils::Assert(parent_index != -1, "cannot find parent in the link");
   }
diff --git a/src/allreduce_base.h b/src/allreduce_base.h
index d5172f9f7..436916cda 100644
--- a/src/allreduce_base.h
+++ b/src/allreduce_base.h
@@ -80,7 +80,7 @@ class AllreduceBase : public IEngine {
    */
   virtual void Broadcast(void *sendrecvbuf_, size_t total_size, int root) {
     utils::Assert(TryBroadcast(sendrecvbuf_, total_size, root) == kSuccess,
-                  "Allreduce failed");
+                  "Broadcast failed");
   }
   /*!
    * \brief load latest check point
diff --git a/src/rabit-inl.h b/src/rabit-inl.h
index c38766bbb..631686582 100644
--- a/src/rabit-inl.h
+++ b/src/rabit-inl.h
@@ -103,7 +103,7 @@ inline void Broadcast(std::vector<DType> *sendrecv_data, int root) {
     sendrecv_data->resize(size);
   }
   if (size != 0) {
-    Broadcast(&sendrecv_data[0], size * sizeof(DType), root);
+    Broadcast(&(*sendrecv_data)[0], size * sizeof(DType), root);
   }
 }
 inline void Broadcast(std::string *sendrecv_data, int root) {
@@ -113,7 +113,7 @@ inline void Broadcast(std::string *sendrecv_data, int root) {
     sendrecv_data->resize(size);
   }
   if (size != 0) {
-    Broadcast(&sendrecv_data[0], size * sizeof(char), root);
+    Broadcast(&(*sendrecv_data)[0], size * sizeof(char), root);
   }
 }
 
diff --git a/src/rabit_master.py b/src/rabit_master.py
index 85b981972..1cfc00dc0 100644
--- a/src/rabit_master.py
+++ b/src/rabit_master.py
@@ -77,6 +77,8 @@ class SlaveEntry:
         self.sock.sendint(rank)
         # send parent rank
         self.sock.sendint((rank + 1) / 2 - 1)
+        # send world size
+        self.sock.sendint(nslave)
         while True:
             ngood = self.sock.recvint()
             goodset = set([])
@@ -88,8 +90,6 @@ class SlaveEntry:
             for r in badset:
                 if r in wait_conn:
                     conset.append(r)
-            print 'rank=%d' % rank
-            print 'conset=%s' % str(conset)
             self.sock.sendint(len(conset))
             self.sock.sendint(len(badset) - len(conset))
             for r in conset:
@@ -109,7 +109,6 @@ class SlaveEntry:
             for r in rmset:
                 wait_conn.pop(r, None)
             self.wait_accept = len(badset) - len(conset)
-            print 'wait=%d' % self.wait_accept
             return rmset
     
 class Master:
diff --git a/test/test_allreduce.cpp b/test/test_allreduce.cpp
index 625d9592a..707b1a22a 100644
--- a/test/test_allreduce.cpp
+++ b/test/test_allreduce.cpp
@@ -80,7 +80,7 @@ int main(int argc, char *argv[]) {
   TestSum(mock, n);
   utils::LogPrintf("[%d] !!!TestSum pass\n", rank);
   int step = std::max(nproc / 3, 1);
-  for (int i = 0; i < nproc; i += step) {
+  for (int i = 0; i < nproc; i += step) {    
     TestBcast(mock, n, i);
   }
   utils::LogPrintf("[%d] !!!TestBcast pass\n", rank);