SIGSEGV with PHP 8.5

[HeenaBansal20]

SIGSEGV with PHP 8.5 on 2.3.0

backtrace

* thread #1, name = 'php', stop reason = signal SIGSEGV: address not mapped to object (fault address=0x57b9d9c0)
  * frame #0: 0x00007fffedea6ea1 libodbc.so.2`SQLSetEnvAttr + 49
    frame #1: 0x00007fffede443f0 ibm_db2.so`_php_db2_connect_helper(execute_data=0x00007ffff4c173f0, return_value=0x00007ffff4c172e0, pconn_res=0x00007fffffffae58, isPersistent=0) at ibm_db2.c:2499:18
    frame #2: 0x00007fffede44bf3 ibm_db2.so`zif_db2_connect(execute_data=0x00007ffff4c173f0, return_value=0x00007ffff4c172e0) at ibm_db2.c:2870:14
    frame #3: 0x000055555604d7ec php`ZEND_DO_ICALL_SPEC_OBSERVER_HANDLER at zend_vm_execute.h:1487:2
    frame #4: 0x00005555560ced69 php`execute_ex(ex=0x00007ffff4c17020) at zend_vm_execute.h:115956:5
    frame #5: 0x00005555560d47a7 php`zend_execute(op_array=0x00007ffff4c83140, return_value=0x0000000000000000) at zend_vm_execute.h:121434:2
    frame #6: 0x0000555556178e52 php`zend_execute_script(type=8, retval=0x0000000000000000, file_handle=0x00007fffffffc650) at zend.c:1977:3
    frame #7: 0x0000555555f167c6 php`php_execute_script_ex(primary_file=0x00007fffffffc650, retval=0x0000000000000000) at main.c:2640:13
    frame #8: 0x0000555555f1694c php`php_execute_script(primary_file=0x00007fffffffc650) at main.c:2680:9
    frame #9: 0x000055555617b564 php`do_cli(argc=9, argv=0x0000555557753a60) at php_cli.c:951:5
    frame #10: 0x000055555617c5c8 php`main(argc=9, argv=0x0000555557753a60) at php_cli.c:1362:18
    frame #11: 0x00007ffff6b8ad90 libc.so.6`__libc_start_call_main(main=(php`main at php_cli.c:1190:1), argc=9, argv=0x00007fffffffda28) at libc_start_call_main.h:58:16
    frame #12: 0x00007ffff6b8ae40 libc.so.6`__libc_start_main_impl(main=(php`main at php_cli.c:1190:1), argc=9, argv=0x00007fffffffda28, init=<unavailable>, fini=<unavailable>, rtld_fini=<unavailable>, stack_end=0x00007fffffffda18) at libc-start.c:392:3

Frame 3:

Frame2:

frame 3

stack trace

php script

$configuration = getEnvironmentConfiguration('IBM_DB2');
$host = $configuration['host'];
$port = $configuration['port'];
$user = $configuration['uid'];
$password = $configuration['pwd'];
$database = $configuration['database'];

    $conn_string = "DRIVER={IBM DB2 ODBC DRIVER};DATABASE=$database;" .
                   "HOSTNAME=$host;PORT=$port;PROTOCOL=TCPIP;UID=$user;PWD=$password;";
    $conn = db2_connect($conn_string, '', '');

    // Connection successful
    $stmt = db2_exec($conn, 'SELECT * FROM SYSCAT.REFERENCES');

    // Statement executed successfully
    $preparedStmt = db2_prepare($conn, 'SELECT * FROM SYSCAT.REFERENCES SC WHERE SC.TABNAME = ?');

    // Prepared statement created successfully
    db2_bind_param($preparedStmt, 1, "SYSCAT.REFERENCES", DB2_PARAM_IN);
    db2_execute($preparedStmt, array("SYSCAT.REFERENCES"));

    $ret = db2_exec($conn, 'SELECT * FROM SYSCAT.REFERENCES');
    var_dump($ret);
    db2_free_stmt($preparedStmt);

    // Close the statement
    db2_free_stmt($stmt);

    // Close the connection when done
    db2_close($conn);

[HeenaBansal20]

@NattyNarwhal , can you look at this.

[NattyNarwhal]

How are you building against the DB2 library? I see a libodbc.so frame, but the clidriver package lacks it.

What I think might be going on is that you're hitting ELF symbol namespacing issues - that is, SQLSetEnvAttr exists in both libodbc.so and libdb2.so, and the dynamic linker doesn't care which it loads. I'm guessing if you omit loading the ODBC extensions, this might work?.

[HeenaBansal20]

@NattyNarwhal , I am building IBM db2 as below in our customized php image dockerfile.

wget -qO- "https://github.com/ibmdb/db2drivers/raw/main/clidriver/linuxx64_odbc_cli.tar.gz" | tar -zxf - -C /usr/src; \
    cp -rf /usr/src/clidriver/lib/* /usr/local/lib/.; \
    cp -rf /usr/src/clidriver/include/* /usr/local/include/.; \
    yes '' | pecl install ibm_db2-2.3.0&& \
    echo "extension=ibm_db2.so" >> "$PHP_INI_DIR/conf.d/ibm_db2.ini"; \
    rm -rf /usr/src/clidriver; \

[NattyNarwhal]

That looks fine, so I think it really is an issue with dynamic linker limitations. I suspect it's pulling SQLSetEnvAttr from i.e. unixODBC/iODBC instead of libdb2. If disabling odbc+PDO_ODBC works...

[HeenaBansal20]

@NattyNarwhal , I can try that but it is only getting triggered for PHP 8.5 and not PHP 8.4 where rest of the extensions drivers are same except the PHP version difference .

[NattyNarwhal]

That's what's confusing me too as I would think the linker would have the same behaviour across PHP versions, but there might be version differences.