diff --git a/usr.sbin/mpsutil/mps_cmd.c b/usr.sbin/mpsutil/mps_cmd.c
index 8e1e431d65f3..60c0a60b006b 100644
--- a/usr.sbin/mpsutil/mps_cmd.c
+++ b/usr.sbin/mpsutil/mps_cmd.c
@@ -651,27 +651,32 @@ mps_pass_command(int fd, void *req, uint32_t req_len, void *reply,
 {
 	struct mprs_pass_thru pass;
 
+	bzero(&pass, sizeof(pass));
 	pass.PtrRequest = (uint64_t)(uintptr_t)req;
 	pass.PtrReply = (uint64_t)(uintptr_t)reply;
-	pass.PtrData = (uint64_t)(uintptr_t)data_in;
-	pass.PtrDataOut = (uint64_t)(uintptr_t)data_out;
 	pass.RequestSize = req_len;
 	pass.ReplySize = reply_len;
-	pass.DataSize = datain_len;
-	pass.DataOutSize = dataout_len;
 	if (datain_len && dataout_len) {
+		pass.PtrData = (uint64_t)(uintptr_t)data_in;
+		pass.PtrDataOut = (uint64_t)(uintptr_t)data_out;
+		pass.DataSize = datain_len;
+		pass.DataOutSize = dataout_len;
 		if (is_mps) {
 			pass.DataDirection = MPS_PASS_THRU_DIRECTION_BOTH;
 		} else {
 			pass.DataDirection = MPR_PASS_THRU_DIRECTION_BOTH;
 		}
 	} else if (datain_len) {
+		pass.PtrData = (uint64_t)(uintptr_t)data_in;
+		pass.DataSize = datain_len;
 		if (is_mps) {
 			pass.DataDirection = MPS_PASS_THRU_DIRECTION_READ;
 		} else {
 			pass.DataDirection = MPR_PASS_THRU_DIRECTION_READ;
 		}
 	} else if (dataout_len) {
+		pass.PtrData = (uint64_t)(uintptr_t)data_out;
+		pass.DataSize = dataout_len;
 		if (is_mps) {
 			pass.DataDirection = MPS_PASS_THRU_DIRECTION_WRITE;
 		} else {