diff --git a/scst/src/dev_handlers/scst_user.c b/scst/src/dev_handlers/scst_user.c
index 3724b8640..73a43eae1 100644
--- a/scst/src/dev_handlers/scst_user.c
+++ b/scst/src/dev_handlers/scst_user.c
@@ -1498,7 +1498,8 @@ static int dev_user_process_reply_exec(struct scst_user_cmd *ucmd,
 			 * We have an empty SG, so can't call
 			 * scst_set_resp_data_len()
 			 */
-			cmd->resp_data_len = ereply->resp_data_len;
+			WARN_ON(ereply->resp_data_len != 0);
+			cmd->resp_data_len = 0;
 			cmd->resid_possible = 1;
 		} else
 			scst_set_resp_data_len(cmd, ereply->resp_data_len);
diff --git a/scst/src/scst_lib.c b/scst/src/scst_lib.c
index 17979082f..754c7d0bb 100644
--- a/scst/src/scst_lib.c
+++ b/scst/src/scst_lib.c
@@ -5987,13 +5987,14 @@ void scst_copy_sg(struct scst_cmd *cmd, enum scst_sg_copy_dir copy_dir)
 	} else {
 		src_sg = cmd->sg;
 		dst_sg = cmd->tgt_i_sg;
-		to_copy = cmd->resp_data_len;
+		to_copy = cmd->adjusted_resp_data_len;
 	}
 
 	TRACE_MEM("cmd %p, copy_dir %d, src_sg %p, dst_sg %p, to_copy %lld",
 		cmd, copy_dir, src_sg, dst_sg, (long long)to_copy);
 
-	if (unlikely(src_sg == NULL) || unlikely(dst_sg == NULL)) {
+	if (unlikely(src_sg == NULL) || unlikely(dst_sg == NULL) ||
+	    unlikely(to_copy == 0)) {
 		/*
 		 * It can happened, e.g., with scst_user for cmd with delay
 		 * alloc, which failed with Check Condition.