diff --git a/drivers/infiniband/hw/irdma/cm.c b/drivers/infiniband/hw/irdma/cm.c
index 195aa9ea18b6ca74c24dc7c45a24d693cedece9b..48c2a303e9ecc973e79a10e173d8a3a46dcbf54e 100644
--- a/drivers/infiniband/hw/irdma/cm.c
+++ b/drivers/infiniband/hw/irdma/cm.c
@@ -337,7 +337,7 @@ static struct irdma_puda_buf *irdma_form_ah_cm_frame(struct irdma_cm_node *cm_no
 
 	pktsize = sizeof(*tcph) + opts_len + hdr_len + pd_len;
 
-	memset(buf, 0, pktsize);
+	memset(buf, 0, sizeof(*tcph));
 
 	sqbuf->totallen = pktsize;
 	sqbuf->tcphlen = sizeof(*tcph) + opts_len;