#32675 [Opn]: mysql_fetch_field() causes segmentation fault

ID: 32675 User updated by: michael at cosby dot dhs dot org Reported By: michael at cosby dot dhs dot org Status: Open Bug Type: MySQL related Operating System: Linux 2.6 PHP Version: 5.0.4 New Comment: It appears that I'm already using the external mysql client library, or I'm reading phpinfo() wrong: MySQL Support enabled Active Persistent Links 0 Active Links 0 Client API version 4.0.21 MYSQL_MODULE_TYPE external MYSQL_SOCKET /tmp/mysql.sock MYSQL_INCLUDE -I/usr/include/mysql MYSQL_LIBS -L/usr/lib -lmysqlclient Previous Comments: ------------------------------------------------------------------------ [2005-04-11 20:04:08] michael at cosby dot dhs dot org For the libraries, it appears that my PHP is *not* compiling with the 4.1.11 client library, but with a 4.0.21 client library. I'm trying to get it to compile with with the 4.1.11 library to see what happens, but I doubt that will fix it since this same 4.0.21 client library works fine with PHP 5.0.2. ------------------------------------------------------------------------ [2005-04-11 20:01:16] michael at cosby dot dhs dot org It looks like my query cache is already disabled: mysql> show variables; +---------------------------------+----------------------------+ | Variable_name | Value | +---------------------------------+----------------------------+ ... | query_cache_limit | 1048576 | | query_cache_min_res_unit | 4096 | | query_cache_size | 0 | | query_cache_type | ON | | query_cache_wlock_invalidate | OFF | ... From the mysql manual at http://dev.mysql.com/doc/mysql/en/query-cache.html: " To disable the query cache at server startup, set the query_cache_size system variable to 0. By disabling the query cache code, there is no noticeable overhead. " (I'm not real familiar with the query cache, so I wanted to be 100% sure it was disabled). ------------------------------------------------------------------------ [2005-04-11 19:54:43] georg@php.net Does the problem still exist if you disable MySQL's query cache? ------------------------------------------------------------------------ [2005-04-11 17:56:45] sniper@php.net Try configure PHP using the external mysql client libraries: 1. delete config.cache file 2 run your configure with this change: --with-mysql=/usr (or whatever the install PREFIX is) Also note: /usr/local/lib or /usr/lib are NOT correct values for any PHP configure option!! They're /usr/local and /usr ------------------------------------------------------------------------ [2005-04-11 17:51:40] michael at cosby dot dhs dot org Description: ------------ environment: apache 2.0.52 in multi-threaded mode mysql 4.1.11 (and 4.1.6-gamma) PHP 5.0.4 php configuration: ./configure --with-apxs2=/usr/sbin/apxs \ --with-zlib --enable-calendar \ --with-gd --with-mhash \ --with-xsl --enable-memory-limit \ --prefix=/home/php --with-mysql \ --with-openssl --with-jpeg-dir=/usr/lib \ --with-gettext \ --with-curl=/usr/local/lib Notes: * This bug does not occur if I use PHP 5.0.2 in the same environment instead of PHP 5.0.4. * It's possible that the fix for bug #31288 is related to this issue. This code does *not* call the (deprecated) function mysql_list_fields() at all. Reproduce code: --------------- The following code snippet (taken from WordPress wp-includes/wp-db.php, a blogging program): while ($i < mysql_num_fields($this->result)) { $this->col_info[$i] = mysql_fetch_field($this->result); $i++; } Even a single invocation of mysql_fetch_field() will cause the seg. fault. Nothing is written to the server's error log from PHP itself. Expected result: ---------------- Code inside a script should not cause a seg. fault. Actual result: -------------- When using the code snippet specified, the apache child running the request seg. faults. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=32675&edit=1