diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 212b12ab51..08609f23dd 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -311,6 +311,13 @@ ExecComputeStoredGenerated(EState *estate, TupleTableSlot *slot)
 
 			val = ExecEvalExpr(resultRelInfo->ri_GeneratedExprs[i], econtext, &isnull);
 
+			/*
+			 * We must make a copy of val as we have no guarantees about where
+			 * memory for a pass-by-reference Datum is located.
+			 */
+			if (!isnull)
+				val = datumCopy(val, attr->attbyval, attr->attlen);
+
 			values[i] = val;
 			nulls[i] = isnull;
 		}
diff --git a/src/test/regress/expected/generated.out b/src/test/regress/expected/generated.out
index 8cffef0477..f87c86a8ce 100644
--- a/src/test/regress/expected/generated.out
+++ b/src/test/regress/expected/generated.out
@@ -320,6 +320,18 @@ SELECT * FROM gtest2;
  1 |  
 (1 row)
 
+-- simple column reference for varlena types
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
+INSERT INTO gtest_varlena (a) VALUES(NULL);
+SELECT * FROM gtest_varlena ORDER BY a;
+          a           |          b           
+----------------------+----------------------
+ 01234567890123456789 | 01234567890123456789
+                      | 
+(2 rows)
+
+DROP TABLE gtest_varlena;
 -- composite types
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
diff --git a/src/test/regress/sql/generated.sql b/src/test/regress/sql/generated.sql
index ff5c8607de..bdcedbb991 100644
--- a/src/test/regress/sql/generated.sql
+++ b/src/test/regress/sql/generated.sql
@@ -145,6 +145,13 @@ CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED)
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
+-- simple column reference for varlena types
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
+INSERT INTO gtest_varlena (a) VALUES(NULL);
+SELECT * FROM gtest_varlena ORDER BY a;
+DROP TABLE gtest_varlena;
+
 -- composite types
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (