diff --git a/include/spdk_internal/log.h b/include/spdk_internal/log.h
index 0c44a4f07..0993d1016 100644
--- a/include/spdk_internal/log.h
+++ b/include/spdk_internal/log.h
@@ -98,4 +98,11 @@ __attribute__((constructor)) static void register_flag_##flag(void) \
 #define SPDK_LOGDUMP(...) do { } while (0)
 #endif
 
+#define SPDK_ERRLOGDUMP(LABEL, BUF, LEN)				\
+	do {								\
+		if ((LEN)) {						\
+			spdk_log_dump(stderr, (LABEL), (BUF), (LEN));	\
+		}							\
+	} while (0)
+
 #endif /* SPDK_INTERNAL_LOG_H */
diff --git a/lib/iscsi/iscsi.c b/lib/iscsi/iscsi.c
index 387b42fce..1f6207b56 100644
--- a/lib/iscsi/iscsi.c
+++ b/lib/iscsi/iscsi.c
@@ -4446,6 +4446,12 @@ init_login_reject_response(struct spdk_iscsi_pdu *pdu, struct spdk_iscsi_pdu *rs
 	rsph->itt = pdu->bhs.itt;
 }
 
+static void
+iscsi_pdu_dump(struct spdk_iscsi_pdu *pdu)
+{
+	SPDK_ERRLOGDUMP("PDU", (uint8_t *)&pdu->bhs, ISCSI_BHS_LEN);
+}
+
 int
 spdk_iscsi_execute(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)
 {
@@ -4489,6 +4495,7 @@ spdk_iscsi_execute(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)
 		return SPDK_ISCSI_LOGIN_ERROR_RESPONSE;
 	} else if (conn->state == ISCSI_CONN_STATE_INVALID) {
 		SPDK_ERRLOG("before Full Feature\n");
+		iscsi_pdu_dump(pdu);
 		return SPDK_ISCSI_CONNECTION_FATAL;
 	}