MDEV-18272 InnoDB fails to rollback after exceeding FOREIGN KEY recursion depth

row_mysql_handle_errors(): Correct the wrong error handling for
the code DB_FOREIGN_EXCEED_MAX_CASCADE that was introduced in

https://github.com/mysql/mysql-server/commit/c0923d396aef46799883390e9dcf7bbf173e4a03

    commit 35f5429eda94f2ce87e453653cd22298d5851cfa
    Author: Jimmy Yang <jimmy.yang@oracle.com>
    Date:   Wed Oct 6 06:55:34 2010 -0700

        Manual port Bug #Bug #54582 "stack overflow when opening many tables
        linked with foreign keys at once" from mysql-5.1-security to
        mysql-5.5-security again.

        rb://391 approved by Heikki

No known test case exists for repeating the bug before MariaDB 10.2.
The scenario should be that DB_FOREIGN_EXCEED_MAX_CASCADE is returned,
then InnoDB wrongly skips the rollback to the start of the current
row operation, and finally the SQL layer commits the transaction.
Normally the SQL layer would roll back either the entire transaction or
to the start of the statement. In the faulty scenario, InnoDB would
leave the transaction in an inconsistent state, and the SQL layer could
commit the transaction.

2 files changed, 12 insertions, 8 deletions

diff --git a/storage/innobase/row/row0mysql.c b/storage/innobase/row/row0mysql.c
index 8804e2c4e03..c16d1b8ea36 100644
--- a/storage/innobase/row/row0mysql.c
+++ b/storage/innobase/row/row0mysql.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2000, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2019, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -572,8 +573,7 @@ handle_new_error:
 	switch (err) {
 	case DB_LOCK_WAIT_TIMEOUT:
 		if (row_rollback_on_timeout) {
-			trx_general_rollback_for_mysql(trx, NULL);
-			break;
+			goto rollback;
 		}
 		/* fall through */
 	case DB_DUPLICATE_KEY:
@@ -586,6 +586,7 @@ handle_new_error:
 	case DB_TOO_MANY_CONCURRENT_TRXS:
 	case DB_OUT_OF_FILE_SPACE:
 	case DB_INTERRUPTED:
+	rollback_to_savept:
 		if (savept) {
 			/* Roll back the latest, possibly incomplete
 			insertion or update */
@@ -609,6 +610,7 @@ handle_new_error:
 
 	case DB_DEADLOCK:
 	case DB_LOCK_TABLE_FULL:
+	rollback:
 		/* Roll back the whole transaction; this resolution was added
 		to version 3.23.43 */
 
@@ -638,14 +640,14 @@ handle_new_error:
 		      "InnoDB: you dump the tables, look at\n"
 		      "InnoDB: " REFMAN "forcing-innodb-recovery.html"
 		      " for help.\n", stderr);
-		break;
+		goto rollback_to_savept;
 	case DB_FOREIGN_EXCEED_MAX_CASCADE:
 		fprintf(stderr, "InnoDB: Cannot delete/update rows with"
 			" cascading foreign key constraints that exceed max"
 			" depth of %lu\n"
 			"Please drop excessive foreign constraints"
 			" and try again\n", (ulong) DICT_FK_MAX_RECURSIVE_LOAD);
-		break;
+		goto rollback_to_savept;
 	default:
 		fprintf(stderr, "InnoDB: unknown error code %lu\n",
 			(ulong) err);
diff --git a/storage/xtradb/row/row0mysql.c b/storage/xtradb/row/row0mysql.c
index 5b01adf7c82..a17a8d59b83 100644
--- a/storage/xtradb/row/row0mysql.c
+++ b/storage/xtradb/row/row0mysql.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2000, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2019, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -574,8 +575,7 @@ handle_new_error:
 	switch (err) {
 	case DB_LOCK_WAIT_TIMEOUT:
 		if (row_rollback_on_timeout) {
-			trx_general_rollback_for_mysql(trx, NULL);
-			break;
+			goto rollback;
 		}
 		/* fall through */
 	case DB_DUPLICATE_KEY:
@@ -588,6 +588,7 @@ handle_new_error:
 	case DB_TOO_MANY_CONCURRENT_TRXS:
 	case DB_OUT_OF_FILE_SPACE:
 	case DB_INTERRUPTED:
+	rollback_to_savept:
 		if (savept) {
 			/* Roll back the latest, possibly incomplete
 			insertion or update */
@@ -611,6 +612,7 @@ handle_new_error:
 
 	case DB_DEADLOCK:
 	case DB_LOCK_TABLE_FULL:
+	rollback:
 		/* Roll back the whole transaction; this resolution was added
 		to version 3.23.43 */
 
@@ -640,14 +642,14 @@ handle_new_error:
 		      "InnoDB: you dump the tables, look at\n"
 		      "InnoDB: " REFMAN "forcing-innodb-recovery.html"
 		      " for help.\n", stderr);
-		break;
+		goto rollback_to_savept;
 	case DB_FOREIGN_EXCEED_MAX_CASCADE:
 		fprintf(stderr, "InnoDB: Cannot delete/update rows with"
 			" cascading foreign key constraints that exceed max"
 			" depth of %lu\n"
 			"Please drop excessive foreign constraints"
 			" and try again\n", (ulong) DICT_FK_MAX_RECURSIVE_LOAD);
-		break;
+		goto rollback_to_savept;
 	default:
 		fprintf(stderr, "InnoDB: unknown error code %lu\n",
 			(ulong) err);