MDEV-16125 Crash or ASAN heap-buffer-overflow in...

MDEV-16125 Crash or ASAN heap-buffer-overflow in mach_read_from_n_little_endian upon ALTER TABLE with blob

- Virtual column should be considered only to find the respective non-null fields.
But virtual column can never changed from NULL to NOT NULL.

mysql-test/suite/innodb/r/alter_not_null.result

@@ -79,3 +79,10 @@ DROP TABLE t1;
 CREATE TABLE t1 (a INT, v INT AS (a), d INT NOT NULL, e INT) ENGINE=InnoDB;
 ALTER TABLE t1 FORCE, ALGORITHM=INPLACE;
 DROP TABLE t1;
+#
+# MDEV-16126 Crash or ASAN heap-buffer-overflow in
+# mach_read_from_n_little_endian upon ALTER TABLE with blob
+#
+CREATE TABLE t1(a INT, v INT AS (a), b INT, c BLOB) ENGINE=InnoDB;
+ALTER TABLE t1 ADD PRIMARY KEY(b);
+DROP TABLE t1;

mysql-test/suite/innodb/t/alter_not_null.test

@@ -64,3 +64,12 @@ DROP TABLE t1;
 CREATE TABLE t1 (a INT, v INT AS (a), d INT NOT NULL, e INT) ENGINE=InnoDB;
 ALTER TABLE t1 FORCE, ALGORITHM=INPLACE;
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-16126 Crash or ASAN heap-buffer-overflow in
+--echo # mach_read_from_n_little_endian upon ALTER TABLE with blob
+--echo #
+
+CREATE TABLE t1(a INT, v INT AS (a), b INT, c BLOB) ENGINE=InnoDB;
+ALTER TABLE t1 ADD PRIMARY KEY(b);
+DROP TABLE t1;

storage/innobase/handler/handler0alter.cc

@@ -3360,9 +3360,12 @@ innobase_build_col_map(
 
 				if (field->real_maybe_null()
 				    && !altered_field->real_maybe_null()) {
+					/* Don't consider virtual column.
+					NULL to NOT NULL is not applicable
+					for virtual column. */
 					innobase_build_col_map_add(
 						heap, dtuple_get_nth_field(
-							defaults, i + num_v),
+							defaults, i),
 						altered_field,
 						dict_table_is_comp(new_table));
 				}