This is a patch for bug#41569.

"mysql_upgrade (ver 5.1) add 3 fields to mysql.proc table but does
not set values".
            
mysql_upgrade (ver 5.1) adds 3 fields (character_set_client, 
collation_connection and db_collation) to the mysql.proc table, but 
does not set any values. When we run stored procedures, which were 
created with mysql 5.0, a warning is logged into the error log.
            
The solution to this is for mysql_upgrade to set default best guess
values for these fields. A warning is also written during upgrade, to
make the user aware that default values are set.

client/mysql_upgrade.c

@@ -778,6 +778,10 @@ static int run_sql_fix_privilege_tables(void)
         found_real_errors++;
         print_line(line);
       }
+      else if (strncmp(line, "WARNING", 7) == 0)
+      {
+        print_line(line);
+      }
     } while ((line= get_line(line)) && *line);
   }
 

mysql-test/r/mysql_upgrade.result

@@ -127,3 +127,45 @@ mysql.time_zone_transition                         OK
 mysql.time_zone_transition_type                    OK
 mysql.user                                         OK
 set GLOBAL sql_mode=default;
+#
+# Bug #41569 mysql_upgrade (ver 5.1) add 3 fields to mysql.proc table 
+# but does not set values.
+#
+CREATE PROCEDURE testproc() BEGIN END;
+UPDATE mysql.proc SET character_set_client = NULL WHERE name LIKE 'testproc';
+UPDATE mysql.proc SET collation_connection = NULL WHERE name LIKE 'testproc';
+UPDATE mysql.proc SET db_collation = NULL WHERE name LIKE 'testproc';
+WARNING: NULL values of the 'character_set_client' column ('mysql.proc' table) have been updated with a default value (latin1). Please verify if necessary.
+WARNING: NULL values of the 'collation_connection' column ('mysql.proc' table) have been updated with a default value (latin1_swedish_ci). Please verify if necessary.
+WARNING: NULL values of the 'db_collation' column ('mysql.proc' table) have been updated with default values. Please verify if necessary.
+mtr.global_suppressions                            OK
+mtr.test_suppressions                              OK
+mysql.columns_priv                                 OK
+mysql.db                                           OK
+mysql.event                                        OK
+mysql.func                                         OK
+mysql.general_log
+Error    : You can't use locks with log tables.
+status   : OK
+mysql.help_category                                OK
+mysql.help_keyword                                 OK
+mysql.help_relation                                OK
+mysql.help_topic                                   OK
+mysql.host                                         OK
+mysql.ndb_binlog_index                             OK
+mysql.plugin                                       OK
+mysql.proc                                         OK
+mysql.procs_priv                                   OK
+mysql.servers                                      OK
+mysql.slow_log
+Error    : You can't use locks with log tables.
+status   : OK
+mysql.tables_priv                                  OK
+mysql.time_zone                                    OK
+mysql.time_zone_leap_second                        OK
+mysql.time_zone_name                               OK
+mysql.time_zone_transition                         OK
+mysql.time_zone_transition_type                    OK
+mysql.user                                         OK
+CALL testproc();
+DROP PROCEDURE testproc;

mysql-test/t/mysql_upgrade.test

@@ -89,3 +89,20 @@ DROP USER mysqltest1@'%';
 set GLOBAL sql_mode='STRICT_ALL_TABLES,ANSI_QUOTES,NO_ZERO_DATE';
 --exec $MYSQL_UPGRADE --skip-verbose --force 2>&1
 eval set GLOBAL sql_mode=default;
+
+
+--echo #
+--echo # Bug #41569 mysql_upgrade (ver 5.1) add 3 fields to mysql.proc table 
+--echo # but does not set values.
+--echo #
+
+# Create a stored procedure and set the fields in question to null. 
+# When running mysql_upgrade, a warning should be written.
+
+CREATE PROCEDURE testproc() BEGIN END;
+UPDATE mysql.proc SET character_set_client = NULL WHERE name LIKE 'testproc';
+UPDATE mysql.proc SET collation_connection = NULL WHERE name LIKE 'testproc';
+UPDATE mysql.proc SET db_collation = NULL WHERE name LIKE 'testproc';
+--exec $MYSQL_UPGRADE --skip-verbose --force 2>&1
+CALL testproc();
+DROP PROCEDURE testproc;

scripts/mysql_system_tables_fix.sql

@@ -415,18 +415,48 @@ ALTER TABLE proc ADD character_set_client
 ALTER TABLE proc MODIFY character_set_client
                         char(32) collate utf8_bin DEFAULT NULL;
 
+SELECT CASE WHEN COUNT(*) > 0 THEN 
+CONCAT ("WARNING: NULL values of the 'character_set_client' column ('mysql.proc' table) have been updated with a default value (", @@character_set_client, "). Please verify if necessary.")
+ELSE NULL 
+END 
+AS value FROM proc WHERE character_set_client IS NULL;
+
+UPDATE proc SET character_set_client = @@character_set_client 
+                     WHERE character_set_client IS NULL;
+
 ALTER TABLE proc ADD collation_connection
                      char(32) collate utf8_bin DEFAULT NULL
                      AFTER character_set_client;
 ALTER TABLE proc MODIFY collation_connection
                         char(32) collate utf8_bin DEFAULT NULL;
 
+SELECT CASE WHEN COUNT(*) > 0 THEN 
+CONCAT ("WARNING: NULL values of the 'collation_connection' column ('mysql.proc' table) have been updated with a default value (", @@collation_connection, "). Please verify if necessary.")
+ELSE NULL 
+END 
+AS value FROM proc WHERE collation_connection IS NULL;
+
+UPDATE proc SET collation_connection = @@collation_connection
+                     WHERE collation_connection IS NULL;
+
 ALTER TABLE proc ADD db_collation
                      char(32) collate utf8_bin DEFAULT NULL
                      AFTER collation_connection;
 ALTER TABLE proc MODIFY db_collation
                         char(32) collate utf8_bin DEFAULT NULL;
 
+SELECT CASE WHEN COUNT(*) > 0 THEN 
+CONCAT ("WARNING: NULL values of the 'db_collation' column ('mysql.proc' table) have been updated with default values. Please verify if necessary.")
+ELSE NULL
+END
+AS value FROM proc WHERE db_collation IS NULL;
+
+UPDATE proc AS p SET db_collation  = 
+                     ( SELECT DEFAULT_COLLATION_NAME 
+                       FROM INFORMATION_SCHEMA.SCHEMATA 
+                       WHERE SCHEMA_NAME = p.db)
+                     WHERE db_collation IS NULL;
+
 ALTER TABLE proc ADD body_utf8 longblob DEFAULT NULL
                      AFTER db_collation;
 ALTER TABLE proc MODIFY body_utf8 longblob DEFAULT NULL;