Description:
------------
Trying to use a Mysqli_Stmt object after the Mysql object is clean result in segfault.

Notice: only with libmysqlclient (no segfault with mysqlnd).

I haven't find a simple solution to check if the link oject is still valid from the stmt object...


Test script:
---------------
$mysqli = new mysqli($host, $user, $pass, $db);
$read_stmt = $mysqli->prepare("SELECT 1");
$mysqli = null;
$read_stmt->bind_result($data);

Expected result:
----------------
no segfault.

Actual result:
--------------
Program received signal SIGSEGV, Segmentation fault.

(gdb) bt
#0  0x00007ffff7aedf3c in mysql_stmt_bind_result () from /usr/lib64/mysql/libmysqlclient.so.18
#1  0x0000000000474b59 in mysqli_stmt_bind_result_do_bind (start=0, argc=<optimized out>, args=0x7ffff7ab7cb8, stmt=0x7ffff7ab7560)
    at /tmp/php-5.5.9/ext/mysqli/mysqli_api.c:430
#2  zif_mysqli_stmt_bind_result (ht=<optimized out>, return_value=0x7ffff7ab8dd8, return_value_ptr=<optimized out>, this_ptr=<optimized out>, 
    return_value_used=<optimized out>) at /tmp/php-5.5.9/ext/mysqli/mysqli_api.c:509
#3  0x000000000062667a in zend_do_fcall_common_helper_SPEC (execute_data=0x7ffff7a81260) at /tmp/php-5.5.9/Zend/zend_vm_execute.h:550
#4  0x00000000005a2b38 in execute_ex (execute_data=0x7ffff7a81260) at /tmp/php-5.5.9/Zend/zend_vm_execute.h:363
#5  0x000000000057c14d in zend_execute_scripts (type=type@entry=8, retval=retval@entry=0x0, file_count=file_count@entry=3) at /tmp/php-5.5.9/Zend/zend.c:1316
#6  0x000000000051dae2 in php_execute_script (primary_file=primary_file@entry=0x7fffffffc8b0) at /tmp/php-5.5.9/main/main.c:2506
#7  0x0000000000628734 in do_cli (argc=2, argv=0x9be8b0) at /tmp/php-5.5.9/sapi/cli/php_cli.c:994
#8  0x000000000041a107 in main (argc=2, argv=0x9be8b0) at /tmp/php-5.5.9/sapi/cli/php_cli.c:1378
(gdb) 
#0  0x00007ffff7aedf3c in mysql_stmt_bind_result () from /usr/lib64/mysql/libmysqlclient.so.18
#1  0x0000000000474b59 in mysqli_stmt_bind_result_do_bind (start=0, argc=<optimized out>, args=0x7ffff7ab7cb8, stmt=0x7ffff7ab7560)
    at /tmp/php-5.5.9/ext/mysqli/mysqli_api.c:430
#2  zif_mysqli_stmt_bind_result (ht=<optimized out>, return_value=0x7ffff7ab8dd8, return_value_ptr=<optimized out>, this_ptr=<optimized out>, 
    return_value_used=<optimized out>) at /tmp/php-5.5.9/ext/mysqli/mysqli_api.c:509
#3  0x000000000062667a in zend_do_fcall_common_helper_SPEC (execute_data=0x7ffff7a81260) at /tmp/php-5.5.9/Zend/zend_vm_execute.h:550
#4  0x00000000005a2b38 in execute_ex (execute_data=0x7ffff7a81260) at /tmp/php-5.5.9/Zend/zend_vm_execute.h:363
#5  0x000000000057c14d in zend_execute_scripts (type=type@entry=8, retval=retval@entry=0x0, file_count=file_count@entry=3) at /tmp/php-5.5.9/Zend/zend.c:1316
#6  0x000000000051dae2 in php_execute_script (primary_file=primary_file@entry=0x7fffffffc8b0) at /tmp/php-5.5.9/main/main.c:2506
#7  0x0000000000628734 in do_cli (argc=2, argv=0x9be8b0) at /tmp/php-5.5.9/sapi/cli/php_cli.c:994
#8  0x000000000041a107 in main (argc=2, argv=0x9be8b0) at /tmp/php-5.5.9/sapi/cli/php_cli.c:1378