| Bug #27811 | The variable 'join_tab' is being used without being defined | ||
|---|---|---|---|
| Submitted: | 13 Apr 2007 14:43 | Modified: | 8 May 2007 1:21 |
| Reporter: | Shane Bester (Platinum Quality Contributor) | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Server: General | Severity: | S3 (Non-critical) |
| Version: | 5.0.40-debug | OS: | Windows |
| Assigned to: | Georgi Kodinov | CPU Architecture: | Any |
[13 Apr 2007 14:44]
MySQL Verification Team
stack from the debugger break
Attachment: bug27811_full_stack_5.0.40_debug_windows.txt (text/plain), 3.15 KiB.
[20 Apr 2007 16:01]
Bugs System
A patch for this bug has been committed. After review, it may be pushed to the relevant source trees for release in the next version. You can access the patch from: http://lists.mysql.com/commits/25022 ChangeSet@1.2459, 2007-04-20 19:01:30+03:00, gkodinov@magare.gmz +3 -0 Bug #27811: FORCE_INIT_OF_VARS was not defined for the debug builds on Windows. This caused LINT_INIT macro to be defined as NOP and this triggers false alarms about use of uninitialized with the runtime libs of some Visual Studio versions. Fixed by defining FORCE_INIT_OF_VARS to match the state of the Windows
[30 Apr 2007 12:58]
Bugs System
Pushed into 5.0.42
[30 Apr 2007 12:58]
Bugs System
Pushed into 5.1.18-beta
[8 May 2007 1:21]
Paul DuBois
Noted in 5.0.42, 5.1.18 changelogs. Debug builds on Windows generated false alarms about uninitialized variables with some Visual Studio runtime libraries.
Description: Compile mysqld-debug.exe using full debug libraries on windows using visual studio 2005. Run the testcase, and get the message which I'll type: Debug Error! Program: C:\build\mysql-5.0.40\sql\debug\mysqld-debug.exe Module: C:\build\mysql-5.0.40\sql\debug\mysqld-debug.exe File: c:\build\mysql-5.0.40\sql\sql_select.cpp Line: 10204 Run-Time Check Failure #3 - The variable 'join_tab' is being used without being defined. (Press Retry to debug the application) Stack: ntdll.dll!DbgBreakPoint mysqld-debug.exe!failwithmessage mysqld-debug.exe!_RTC_UninitUse mysqld-debug.exe!do_select mysqld-debug.exe!JOIN::exec mysqld-debug.exe!subselect_single_select_engine::exec mysqld-debug.exe!Item_subselect::exec mysqld-debug.exe!Item_singlerow_subselect::val_int mysqld-debug.exe!Arg_comparator::compare_int_signed mysqld-debug.exe!Arg_comparator::compare mysqld-debug.exe!Item_func_eq::val_int mysqld-debug.exe!Item_equal::add mysqld-debug.exe!Item_equal::update_const mysqld-debug.exe!update_const_equal_items mysqld-debug.exe!join_read_const_table mysqld-debug.exe!make_join_statistics mysqld-debug.exe!JOIN::optimize mysqld-debug.exe!mysql_select mysqld-debug.exe!mysql_explain_union mysqld-debug.exe!mysql_execute_command mysqld-debug.exe!mysql_parse mysqld-debug.exe!dispatch_command mysqld-debug.exe!do_command mysqld-debug.exe!handle_one_connection mysqld-debug.exe!pthread_start mysqld-debug.exe!_callthreadstart mysqld-debug.exe!_threadstart kernel32.dll!FlsSetValue Here's the code place mentioned: if (!join->conds || join->conds->val_int()) { error= (*end_select)(join,join_tab,0); if (error == NESTED_LOOP_OK || error == NESTED_LOOP_QUERY_LIMIT) error= (*end_select)(join,join_tab,1); } join_tab has a value of 0xcccccccc Although the function that is called has join_tab declared as __attribute__((unused)), how can this always be guaranteed ? At least it can make our full debug binaries difficult to use when doing normal testing. This testcase doesn't cause a crash if the warning message is ignored. How to repeat: DROP TABLE IF EXISTS `t1`; CREATE TABLE `t1` ( `c1` char(50), `c2` int) ENGINE=MyISAM; INSERT INTO `t1` VALUES ('a',1); EXPLAIN SELECT * FROM `t1` WHERE `c2` = (SELECT max(2)); Suggested fix: initialize the join_tab to NULL if it's not going to be used.