diff --git a/ompi/mca/pml/ob1/pml_ob1_sendreq.c b/ompi/mca/pml/ob1/pml_ob1_sendreq.c
index 4533db5cf1..00e5ba663d 100644
--- a/ompi/mca/pml/ob1/pml_ob1_sendreq.c
+++ b/ompi/mca/pml/ob1/pml_ob1_sendreq.c
@@ -113,7 +113,9 @@ static int mca_pml_ob1_send_request_free(struct ompi_request_t** request)
                              &(sendreq->req_send.req_base), PERUSE_SEND );
 
     if( true == sendreq->req_send.req_base.req_pml_complete ) {
-        MCA_PML_OB1_SEND_REQUEST_RETURN( sendreq );
+        /* don't free request if other thread running schedule */
+        if(OPAL_THREAD_ADD32(&sendreq->req_lock, 1) == 1)
+            MCA_PML_OB1_SEND_REQUEST_RETURN( sendreq );
     }
 
     OPAL_THREAD_UNLOCK(&ompi_request_lock);
@@ -948,10 +950,15 @@ int mca_pml_ob1_send_request_schedule_exclusive(
                 }
 
                 item = opal_list_get_first(&sendreq->req_send_ranges);
-                OPAL_THREAD_UNLOCK(&sendreq->req_send_range_lock);
 
-                if(opal_list_get_end(&sendreq->req_send_ranges) == item)
+                if(opal_list_get_end(&sendreq->req_send_ranges) == item) {
+                    /* nothing to schedule any more. Exit the outer loop ASAP */
+                    OPAL_ATOMIC_CMPSET_32(&sendreq->req_lock,
+                            sendreq->req_lock, 1);
+                    OPAL_THREAD_UNLOCK(&sendreq->req_send_range_lock);
                     break;
+                }
+                OPAL_THREAD_UNLOCK(&sendreq->req_send_range_lock);
 
                 range = (mca_pml_ob1_send_range_t*)item;
                 prev_bytes_remaining = 0;
@@ -1054,6 +1061,15 @@ int mca_pml_ob1_send_request_schedule_exclusive(
             }
             mca_bml.bml_progress();
         }
+        OPAL_THREAD_LOCK(&ompi_request_lock);
+        if(sendreq->req_send.req_base.req_free_called &&
+                sendreq->req_send.req_base.req_pml_complete) {
+            /* if request already completed and freed put it on a free list */
+            MCA_PML_OB1_SEND_REQUEST_RETURN( sendreq );
+            OPAL_THREAD_UNLOCK(&ompi_request_lock);
+            return MPI_SUCCESS;
+        }
+        OPAL_THREAD_UNLOCK(&ompi_request_lock);
     } while (OPAL_THREAD_ADD32(&sendreq->req_lock,-1) > 0);
 
     return OMPI_SUCCESS;
diff --git a/ompi/mca/pml/ob1/pml_ob1_sendreq.h b/ompi/mca/pml/ob1/pml_ob1_sendreq.h
index 5cce9c608b..e02461fd22 100644
--- a/ompi/mca/pml/ob1/pml_ob1_sendreq.h
+++ b/ompi/mca/pml/ob1/pml_ob1_sendreq.h
@@ -192,7 +192,9 @@ do {
         sendreq->req_send.req_base.req_pml_complete = true;                             \
                                                                                         \
         if( sendreq->req_send.req_base.req_free_called ) {                              \
-            MCA_PML_OB1_SEND_REQUEST_RETURN( sendreq );                                 \
+            /* don't free request if other thread running schedule */                   \
+            if(OPAL_THREAD_ADD32(&sendreq->req_lock, 1) == 1)                           \
+                MCA_PML_OB1_SEND_REQUEST_RETURN( sendreq );                             \
         }                                                                               \
         OPAL_THREAD_UNLOCK(&ompi_request_lock);                                         \
     } while (0)
@@ -222,12 +224,12 @@ static inline void mca_pml_ob1_send_request_schedule(
  */
 
 #define MCA_PML_OB1_SEND_REQUEST_RETURN(sendreq)                        \
-    {                                                                   \
+    do {                                                                \
     /*  Let the base handle the reference counts */                     \
     MCA_PML_BASE_SEND_REQUEST_FINI((&(sendreq)->req_send));             \
     OMPI_FREE_LIST_RETURN( &mca_pml_base_send_requests,                 \
                            (ompi_free_list_item_t*)sendreq);            \
-    }
+    } while(0)
 
 /**
  *  Start the specified request