From: Date: September 26 2007 9:59pm
Subject: bk commit into 5.0 tree (aelkin:1.2526) BUG#26000
List-Archive: http://lists.mysql.com/commits/34573
X-Bug: 26000
Message-Id: <200709261959.l8QJxZMJ009617@koti.dsl.inet.fi>

Below is the list of changes that have just been committed into a local
5.0 repository of elkin. When elkin does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
For information on how to access the public repository
see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet@stripped, 2007-09-26 21:59:17+02:00, aelkin@stripped +1 -0
  Bug #26000 SHOW SLAVE STATUS can crash mysqld during shutdown process
  
  active_mi has been reset (shutdown) at the time of quering with 
  SHOW SLAVE STATUS so that 
  at handling of SHOW an attempt to read its members segfaults.
  
  Fixed with checking the value of active_mi before to call show_master_info()
  Merely send_ok() is invoked when active_mi does not exist.
  A test can not be easiely written.
  
  Notice, there are more analogical cases in the code which require a similar
  treatment (to be reported as a bug separately). 

  sql/sql_parse.cc@stripped, 2007-09-26 21:59:11+02:00, aelkin@stripped +10 -1
    Ignore reporting and send only OK if master info struct has been destoyed.
    As this must be at shutdown merely a warning is sent to the client.

diff -Nrup a/sql/sql_parse.cc b/sql/sql_parse.cc
--- a/sql/sql_parse.cc	2007-08-05 05:53:13 +02:00
+++ b/sql/sql_parse.cc	2007-09-26 21:59:11 +02:00
@@ -2844,7 +2844,16 @@ mysql_execute_command(THD *thd)
     if (check_global_access(thd, SUPER_ACL | REPL_CLIENT_ACL))
       goto error;
     pthread_mutex_lock(&LOCK_active_mi);
-    res = show_master_info(thd,active_mi);
+    if (active_mi != NULL)
+    {
+      res = show_master_info(thd, active_mi);
+    }
+    else
+    {
+      push_warning(thd, MYSQL_ERROR::WARN_LEVEL_WARN, 0,
+                   "the master info structure does not exist");
+      send_ok(thd);
+    }
     pthread_mutex_unlock(&LOCK_active_mi);
     break;
   }