MySQL Bugs: #46003: Valgrind warning in JOIN::init()

Bug #46003	Valgrind warning in JOIN::init()
Submitted:	7 Jul 2009 12:16	Modified:	7 Aug 2009 20:28
Reporter:	Georgi Kodinov	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Optimizer	Severity:	S3 (Non-critical)
Version:	5.1-bk	OS:	Linux (Fedora 10)
Assigned to:	Georgi Kodinov	CPU Architecture:	Any

Description:
I get valgrind warnings like this:
==29177== Source and destination overlap in memcpy(0x4E461A8, 0x4E461A8, 28)
==29177==    at 0x4A0827A: memcpy (mc_replace_strmem.c:402)
==29177==    by 0x6407FE: JOIN::init(THD*, List<Item>&, unsigned long long, sele
ct_result*) (sql_select.h:469)
==29177==    by 0x64094F: JOIN::JOIN(THD*, List<Item>&, unsigned long long, sele
ct_result*) (sql_select.h:418)
==29177==    by 0x72C18F: mysql_select(THD*, Item***, TABLE_LIST*, unsigned int,
 List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsig
ned long long, select_result*, st_select_lex_unit*, st_select_lex*) (sql_select.
cc:2361)
==29177==    by 0x73185C: handle_select(THD*, st_lex*, select_result*, unsigned 
long) (sql_select.cc:268)
==29177==    by 0x69C454: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc
:5012)
==29177==    by 0x69E345: mysql_execute_command(THD*) (sql_parse.cc:2207)
==29177==    by 0x85E0D4: sp_instr_stmt::exec_core(THD*, unsigned int*) (sp_head
.cc:2907)
==29177==    by 0x85E30C: sp_lex_keeper::reset_lex_and_exec_core(THD*, unsigned 
int*, bool, sp_instr*) (sp_head.cc:2735)
==29177==    by 0x86448E: sp_instr_stmt::execute(THD*, unsigned int*) (sp_head.c
c:2849)
==29177==    by 0x86060D: sp_head::execute(THD*) (sp_head.cc:1253)
==29177==    by 0x86139C: sp_head::execute_procedure(THD*, List<Item>*) (sp_head
.cc:1983)
==29177==    by 0x6A4EC7: mysql_execute_command(THD*) (sql_parse.cc:4353)
==29177==    by 0x6A7211: mysql_parse(THD*, char const*, unsigned int, char cons
t**) (sql_parse.cc:5932)
==29177==    by 0x6A8004: dispatch_command(enum_server_command, THD*, char*, uns
igned int) (sql_parse.cc:1213)
==29177==    by 0x6A936C: do_command(THD*) (sql_parse.cc:854) 

How to repeat:
run mysql-test-run.sh --valgrind group_by using valgrind-3.4.0.SVN

Suggested fix:
The JOIN constructor sets fields_list to fields_arg twice : once in an initializer and again in JOIN::init via an assignment.
Fix by either implementing a JOIN::equals() method and comparing the fields_list in JOIN::init() or renaming JOIN::init() to JOIN::init_innter(), taking out the assignment from it and moving to a JOIN::init() that will call JOIN::init_inner() and call JOIN::init_inner from the constructor.

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/78121

3007 Georgi Kodinov	2009-07-07
      Bug #46003: Valgrind warning in JOIN::init()
      
      Don't do double initialization of JOIN::fields_list
      in JOIN::init().

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/78222

2801 Georgi Kodinov	2009-07-08
      Bug #46003 and bug #46034: backported the fixes from azalea.

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/78836

2801 Georgi Kodinov	2009-07-16
      Bug #46003 and bug #46034: backported the fixes from azalea.
      
      ******
      Bug #46042: backported the fix for the valgrind warning from 5.1

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/78847

2785 Georgi Kodinov	2009-07-16
      Bug #46003 and bug #46034: backported the fixes from azalea.

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/78867

2801 Georgi Kodinov	2009-07-16
      Bug #46003 and bug #46034: backported the fixes from azalea.

Pushed into 5.0.85 (revid:davi.arnaut@sun.com-20090804135315-6lfdnk4zjwk7kn7r) (version source revid:davi.arnaut@sun.com-20090804135315-6lfdnk4zjwk7kn7r) (merge vers: 5.0.85) (pib:11)

Pushed into 5.4.4-alpha (revid:alik@sun.com-20090804194615-h40sa098mx4z49qg) (version source revid:dao-gang.qu@sun.com-20090717025250-n2lq5mqibjfdpigu) (merge vers: 5.4.4-alpha) (pib:11)

Pushed into 5.1.38 (revid:davi.arnaut@sun.com-20090804204317-ggodqkik7de6nfpz) (version source revid:davi.arnaut@sun.com-20090804204317-ggodqkik7de6nfpz) (merge vers: 5.1.38) (pib:11)

Noted in 5.0.85, 5.1.38, 5.4.4 changelogs.

Several Valgrind warnings were corrected.

Noted in 5.4.2 changelog because next 5.4 version will be 5.4.2 and not 5.4.4.

Ignore previous comment about 5.4.2.

Pushed into 5.1.39-ndb-6.3.28 (revid:jonas@mysql.com-20091001055605-ap2kiaarr7p40mmv) (version source revid:jonas@mysql.com-20091001055605-ap2kiaarr7p40mmv) (merge vers: 5.1.39-ndb-6.3.28) (pib:11)

Pushed into 5.1.39-ndb-7.0.9 (revid:jonas@mysql.com-20091001072547-kv17uu06hfjhgjay) (version source revid:jonas@mysql.com-20091001071652-irejtnumzbpsbgk2) (merge vers: 5.1.39-ndb-7.0.9) (pib:11)

Pushed into 5.1.39-ndb-7.1.0 (revid:jonas@mysql.com-20091001123013-g9ob2tsyctpw6zs0) (version source revid:jonas@mysql.com-20091001123013-g9ob2tsyctpw6zs0) (merge vers: 5.1.39-ndb-7.1.0) (pib:11)

Pushed into 5.1.39-ndb-6.2.19 (revid:jonas@mysql.com-20091005103850-dwij2dojwpvf5hi6) (version source revid:jonas@mysql.com-20090930185117-bhud4ek1y0hsj1nv) (merge vers: 5.1.39-ndb-6.2.19) (pib:11)

The 5.4 fix has been pushed to 5.4.2.