MPI_Isend: memchecker do not mark send buffer as unaccessible after pml isend invokation

Today's MPI standard mandates the send buffer remains accessible during the send operation.

Signed-off-by: Gilles Gouaillardet <gilles@rist.or.jp>

ompi/mpi/c/isend.c

@@ -13,7 +13,7 @@
  * Copyright (c) 2006-2007 Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2013      Los Alamos National Security, LLC.  All rights
  *                         reserved.
- * Copyright (c) 2015      Research Organization for Information Science
+ * Copyright (c) 2015-2017 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
  * $COPYRIGHT$
  *
@@ -82,9 +82,13 @@ int MPI_Isend(const void *buf, int count, MPI_Datatype type, int dest,
 
     OPAL_CR_ENTER_LIBRARY();
 
-    MEMCHECKER (
-        memchecker_call(&opal_memchecker_base_mem_noaccess, buf, count, type);
-    );
+    /*
+     * today's MPI standard mandates the send buffer remains accessible during the send operation
+     * hence memchecker cannot mark buf as non accessible, but it might mark buf as read-only in
+     * order to trap end user errors. Unfortunatly valgrind does not support marking buffers as read-only,
+     * so there is pretty much nothing we can do here.
+     */
+     
     rc = MCA_PML_CALL(isend(buf, count, type, dest, tag,
                             MCA_PML_BASE_SEND_STANDARD, comm, request));
     OMPI_ERRHANDLER_RETURN(rc, comm, rc, FUNC_NAME);