bzr commit into mysql-6.0-falcon branch (vvaintroub:2792) Bug#38933

[Vladislav Vaintroub]

#At file:///C:/bzr/mysql-6.0-falcon-team/

 2792 Vladislav Vaintroub	2008-08-21
      Bug #38933 - crash if rollback and concurrent DDL operations
      
      Problem : Transaction record list is modified and entries of
      the list are freed during Transaction::rollback.If there is 
      a parallel execution of DDL statement, DDL  will traverse the 
      list and can crash accessing freed memory
      
      Fix: protect record list on Transaction::rollback. The syncObject
      for this purpose has always been syncIndexes and it is used here
      once again. syncIndexes usage is possibly a hack. TODO: have 
      dedicated syncObject for protecting the list.
modified:
  mysql-test/suite/falcon/r/falcon_bug_22165.result
  mysql-test/suite/falcon/t/falcon_bug_22165.test
  storage/falcon/Transaction.cpp

per-file messages:
  mysql-test/suite/falcon/r/falcon_bug_22165.result
    test rollback as well
  mysql-test/suite/falcon/t/falcon_bug_22165.test
    test rollback as well
  storage/falcon/Transaction.cpp
    protect record list during Transaction::rollback
=== modified file 'mysql-test/suite/falcon/r/falcon_bug_22165.result'
--- a/mysql-test/suite/falcon/r/falcon_bug_22165.result	2008-08-04 15:53:52 +0000
+++ b/mysql-test/suite/falcon/r/falcon_bug_22165.result	2008-08-21 13:18:06 +0000
@@ -16,7 +16,10 @@ while v < 10 do
 START TRANSACTION;
 INSERT INTO t1 (a, b) VALUES (v, 'a');
 UPDATE t1 SET c = current_timestamp WHERE a = v;
-COMMIT;
+IF (v < 5)  
+THEN COMMIT;
+ELSE ROLLBACK; 
+END IF;
 SET v = v + 1;
 end while;
 end//

=== modified file 'mysql-test/suite/falcon/t/falcon_bug_22165.test'
--- a/mysql-test/suite/falcon/t/falcon_bug_22165.test	2008-08-04 15:53:52 +0000
+++ b/mysql-test/suite/falcon/t/falcon_bug_22165.test	2008-08-21 13:18:06 +0000
@@ -30,7 +30,10 @@ begin
     START TRANSACTION;
     INSERT INTO t1 (a, b) VALUES (v, 'a');
     UPDATE t1 SET c = current_timestamp WHERE a = v;
-    COMMIT;
+	IF (v < 5)  
+	  	THEN COMMIT;
+	  	ELSE ROLLBACK; 
+ 	END IF;
     SET v = v + 1;
   end while;
 end//
@@ -57,7 +60,7 @@ while ($i)
   --reap
   connection conn2;
   --reap
-  
+
   dec $i;
 }
 --enable_query_log

=== modified file 'storage/falcon/Transaction.cpp'
--- a/storage/falcon/Transaction.cpp	2008-08-18 05:45:29 +0000
+++ b/storage/falcon/Transaction.cpp	2008-08-21 13:18:06 +0000
@@ -403,6 +403,9 @@ void Transaction::rollback()
 	// Rollback pending record versions from newest to oldest in case
 	// there are multiple record versions on a prior record chain
 
+	Sync sync(&syncIndexes, "Transaction::rollback(1.5)");
+	sync.lock(Exclusive);
+
 	while (firstRecord)
 		{
 		record = firstRecord;
@@ -428,6 +431,8 @@ void Transaction::rollback()
 		record->transaction = rollbackTransaction;
 		record->release();
 		}
+	firstRecord = NULL;
+	sync.unlock();
 
 	for (SavePoint *savePoint = savePoints; savePoint; savePoint = savePoint->next)
 		if (savePoint->backloggedRecords)