diff --git a/opal/mca/btl/smcuda/btl_smcuda_fifo.h b/opal/mca/btl/smcuda/btl_smcuda_fifo.h
index ca1257b5c56..56369dba9b3 100644
--- a/opal/mca/btl/smcuda/btl_smcuda_fifo.h
+++ b/opal/mca/btl/smcuda/btl_smcuda_fifo.h
@@ -85,6 +85,8 @@ static void add_pending(struct mca_btl_base_endpoint_t *ep, void *data, bool res
 #define MCA_BTL_SMCUDA_FIFO_WRITE(endpoint_peer, my_smp_rank, peer_smp_rank, hdr, resend,         \
                                   retry_pending_sends, rc)                                        \
     do {                                                                                          \
+        /* memory barrier: ensure writes to the hdr have completed */                             \
+        opal_atomic_wmb();                                                                        \
         sm_fifo_t *fifo = &(mca_btl_smcuda_component.fifo[peer_smp_rank][FIFO_MAP(my_smp_rank)]); \
                                                                                                   \
         if (retry_pending_sends) {                                                                \