1berry/MariaDB-server
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Bug #21467458 - UNINSTALL PLUGIN DAEMON_EXAMPLE CRASHES

Browse Source 
MYSQLD.

DESCRIPTION
===========
Crash occurs when daemon_example plugin is uninstalled
immediately after its installed. This can be reproduced
by installing and uninstalling the plugin repeatedly.

ANALYSIS
========
The daemon_example_plugin_deinit() function of the daemon
example plugin calls pthread_cancel() but doesn't wait for
the worker thread to actually complete before deallocating
the data buffer and closing the file that it writes to.
This is causing SEGFAULT!

FIX
===
Added a pthread_join() to wait for the thread to complete
before doing the cleanup work.

Removed a stray 'x' variable from the example code.

NOTE
====
Have made an entry in .opt file as given below:
--plugin-dir=$DAEMONEXAMPLE_DIR

This is done so that the program takes plugin directory as
../<dbg>/plugin/daemon_example/ instead of
../lib/plugin/
This commit is contained in:
Shishir Jaiswal 2015-09-16 18:58:43 +05:30
parent adf12e6e17
commit 17387bc574
1 changed files with 9 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
plugin/daemon_example/daemon_example.cc
View File

@ -1,4 +1,5 @@
/* Copyright (c) 2006, 2011, Oracle and/or its affiliates. All rights reserved.
/* Copyright (c) 2006, 2015, Oracle and/or its affiliates. All rights
reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@ -46,7 +47,6 @@ pthread_handler_t mysql_heartbeat(void *p)
DBUG_ENTER("mysql_heartbeat");
struct mysql_heartbeat_context *con= (struct mysql_heartbeat_context *)p;
char buffer[HEART_STRING_BUFFER];
unsigned int x= 0;
time_t result;
struct tm tm_tmp;
@ -65,7 +65,6 @@ pthread_handler_t mysql_heartbeat(void *p)
tm_tmp.tm_min,
tm_tmp.tm_sec);
my_write(con->heartbeat_file, (uchar*) buffer, strlen(buffer), MYF(0));
x++;
}
DBUG_RETURN(0);
@ -173,6 +172,13 @@ static int daemon_example_plugin_deinit(void *p)
tm_tmp.tm_min,
tm_tmp.tm_sec);
my_write(con->heartbeat_file, (uchar*) buffer, strlen(buffer), MYF(0));
/*
Need to wait for the hearbeat thread to terminate before closing
the file it writes to and freeing the memory it uses.
*/
pthread_join(con->heartbeat_thread, NULL);
my_close(con->heartbeat_file, MYF(0));
my_free(con);