Mysterious crashes (WAS: Re: Pear fetch script problem on PHP 7.0)

Hi all, Lior, which compiler are you using? You can still reproduce the problem? Can you run it through Valgrind? I'm getting random crashes I can't figure out on 64-bit Linux after just making a very trivial change. :-/ The backtrace is the same up to compile_file() (although maybe that doesn't mean much? hmm). Dmitry, to reproduce, just add another GLOBAL REGISTER variable to zend_vm_execute, and then set it in execute_ex(). An empty file will crash it. It does NOT crash with --enable-debug, nor with certain combinations of optimization level and global register. %r12 with -O2 seems to consistently fail, but with -O3 it might be %r13, etc. Now, the question: Is that little change triggering a bug in GCC 4.8? Or is it somehow revealing a PHP problem?! Thanks, Matt ----- Original Message ----- From: "Lior Kaplan" Sent: Monday, November 23, 2015

Hi, Thanks Ferenc for checking. trying to debug this, I've added "echo var_dump($argv);" in the begining of the script, but now it segfault. before: sh-3.2# /php-7.0.0RC7/sapi/cli/php -n /php-7.0.0RC7/pear/fetch.php " http://5.77.39.20/install-pear-nozlib.phar" pear/install-pear-nozlib.phar Fatal error: Redefinition of parameter $argv in /php-7.0.0RC7/pear/fetch.php on line 3 sh-3.2# /php-7.0.0RC7/sapi/cli/php -n -m [PHP Modules] Core date dom filter hash iconv json libxml mysqlnd openssl pcre PDO pdo_mysql pdo_pgsql pdo_sqlite readline Reflection session SimpleXML SPL sqlite3 standard xml xmlreader xmlwriter zlib [Zend Modules] after: (gdb) r -n /php-7.0.0RC7/pear/fetch.php " http://5.77.39.20/install-pear-nozlib.phar" pear/install-pear-nozlib.phar Starting program: /php-7.0.0RC7/sapi/cli/php -n /php-7.0.0RC7/pear/fetch.php "http://5.77.39.20/install-pear-nozlib.phar" pear/install-pear-nozlib.phar Reading symbols for shared libraries ++++++................................................ done Reading symbols for shared libraries ........................ done Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000010 zend_try_compile_cv (result=0x7fff5fbfe440, ast=0x103e6f100) at zend_compile.c:2178 2178 if (zend_string_equals_literal(name, "this")) { (gdb) bt #0 zend_try_compile_cv (result=0x7fff5fbfe440, ast=0x103e6f100) at zend_compile.c:2178 #1 0x00000001002b7ff1 in zend_compile_simple_var [inlined] () at /php-7.0.0RC7/Zend/zend_compile.c:2226 #2 0x00000001002b7ff1 in zend_compile_var (result=0x7fff5fbfe440, ast=0x103e6f100, type=0) at zend_compile.c:7219 #3 0x00000001002bb46d in zend_compile_args (ast=0xfffffffffffff2f5, fbc=0x103e6f100) at zend_compile.c:2722 #4 0x00000001002b7e62 in zend_compile_call_common (result=0x7fff5fbfe648, args_ast=0xfffffffffffff2f5, fbc=0x10232e050) at zend_compile.c:2810 #5 0x00000001002ba8e5 in zend_compile_call (result=0x7fff5fbfe648, ast=0x103e6f100, type=65523712) at zend_compile.c:3245 #6 0x00000001002b7366 in zend_compile_expr (result=0x7fff5fbfe648, ast=0x103e6f100) at zend_compile.c:7111 #7 0x00000001002b428f in zend_compile_echo [inlined] () at /php-7.0.0RC7/Zend/zend_compile.c:3616 #8 0x00000001002b428f in zend_compile_stmt (ast=0x103e750d0) at zend_compile.c:7007 #9 0x00000001002b7990 in zend_compile_top_stmt (ast=0x103e750d0) at zend_compile.c:6966 #10 0x00000001002b797d in zend_compile_top_stmt (ast=0x103e750e0) at zend_compile.c:6961 #11 0x00000001002b797d in zend_compile_top_stmt (ast=0x103e770a8) at zend_compile.c:6961 #12 0x000000010029e6f2 in compile_file (file_handle=0x7fff5fbfe728, type=65523712) at zend_language_scanner.l:607 #13 0x00000001002cc4dc in zend_execute_scripts (type=8, retval=0x7fff5fbfe990, file_count=1606412688) at zend.c:1422 #14 0x000000010026a1a9 in php_execute_script (primary_file=0x7fff5fbff6d8) at main.c:2471 #15 0x000000010035dad4 in do_cli [inlined] () at /php-7.0.0RC7/sapi/cli/php_cli.c:974 #16 0x000000010035dad4 in main (argc=1606416352, argv=0x7fff5fbff7e0) at php_cli.c:1345 (again, works fine on Linux) Kaplan On Sun, Nov 22, 2015 at 10:51 PM, Andrea Faulds <ajf@ajf.me> wrote:

Hi Lior, Lior Kaplan wrote:

Fatal error: Redefinition of parameter $argv in /php-7.0.0RC7/pear/fetch.php on line 3 make: *** [install-pear] Error 255

This is a strange and rather concerning error message. If I look at the source code of /pear/fetch.php in php-src, line three looks like this:

    function usage($argv) {

$argv here is only specified once in the parameter list, yet it produces an error. Now, presumably this is some sort of conflict with the global variable $argv. But that's a global, not a superglobal, so it really shouldn't cause an error here. This looks like it might be a serious PHP 7 bug. And yet I can't reproduce it by running pear/fetch.php. Is something weird going on here? Thanks. -- Andrea Faulds http://ajf.me/