MySQL Bugs: #33334: mysqltest_embedded crashes when disconnecting before reap

Bug #33334	mysqltest_embedded crashes when disconnecting before reap
Submitted:	18 Dec 2007 15:11	Modified:	11 Apr 2008 14:00
Reporter:	Ingo Strüwing	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Tests: Server	Severity:	S7 (Test Cases)
Version:	5.1.23	OS:	Any
Assigned to:	Alexey Botchkov	CPU Architecture:	Any
Tags:	crash, embedded

Description:
main.alias                     [ fail ]

ERROR: mysqltest returned unexpected code 139, it has probably crashed

Stopping All Servers

#0  THD::clear_data_list (this=0x0) at lib_sql.cc:689
#1  emb_advanced_command (mysql=0x1131960, command=COM_QUERY, header=0x0, header_length=0, arg=0x11d43cd "DROP TABLE IF EXIST t1", arg_length=22, skip_check=1 '\001', stmt=0x0) at lib_sql.cc:80
#2  mysql_send_query (mysql=0x1131960, query=0x11d43cd "DROP TABLE IF EXIST t1", length=22) at client.c:2786
#3  send_one_query (arg=0x1131960) at mysqltest.c:500
#4  start_thread () from /lib/libpthread.so.0
#5  clone () from /lib/libc.so.6

The problem is that cn->mysql->thd is NULL. I guess that 'disconnect' clears the resources for the thread without terminating it.

How to repeat:
Append the following four lines to the end of an arbitrary test case, e.g. alias.test:

connect (con1,localhost,root,,);
send DROP TABLE IF EXIST t1;
disconnect con1;
connection default;

[EOF here, no more statements.]

cd mysql-test && ./mysql-test-run.pl --embedded-server alias

Suggested fix:
Either handle it smoothly and/or report an error about the forgotten 'reap'.

Keep track of the created and ended threads. Before clearing resources of an existing thread, cancel it and wait for it to end. Perhaps pthread_cancel() and pthread_join() could do that.

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/42055

ChangeSet@1.2594, 2008-02-11 15:59:01+04:00, holyfoot@mysql.com +1 -0
  Bug #33334 mysqltest_embedded crashes when disconnecting before reap.
  
  Before breaking the connection we have to check that there's no query
  executing at the moment. Otherwise it can lead to crash in embedded server.

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/42061

ChangeSet@1.2594, 2008-02-11 16:13:03+04:00, holyfoot@mysql.com +1 -0
  Bug #33334 mysqltest_embedded crashes when disconnecting before reap.
  
  Wait until the query thread is finished before we break the connection.

Don't mind the second patch - was sent by mistake.

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/43016

ChangeSet@1.2608, 2008-02-27 00:00:14+04:00, holyfoot@mysql.com +3 -0
  Bug #33334 mysqltest_embedded crashes when disconnecting before reap.
  
  Before breaking the connection we have to check that there's no query
    executing at the moment. Otherwise it can lead to crash in embedded server.

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/44217

ChangeSet@1.2608, 2008-03-19 15:51:22+04:00, holyfoot@mysql.com +3 -0
  Bug #33334 mysqltest_embedded crashes when disconnecting before reap.
  
  Before breaking the connection we have to check that there's no query
    executing at the moment. Otherwise it can lead to crash in embedded server.

Pushed into 5.1.24-rc

Pushed into 5.0.60

Pushed into 6.0.5-alpha

Change in tests only, no user changes to document. Closed w/o further action.