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To: Gregory Beaver <greg@chiaraquartet.net>
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Date: Wed, 16 Jul 2008 22:07:57 +0200
References: <4855D62C.2010902@chiaraquartet.net>
Subject: Re: [PHP-DEV] potential shutdown order issue
From: mls@pooteeweet.org (Lukas Kahwe Smith)

Hi,

Does anyone agree that there is an issue to fix here? Messing with the  
shutdown order is probably the last thing any RM would like to see  
happening ..

regards,
Lukas

On 16.06.2008, at 04:55, Gregory Beaver wrote:

> Hi,
>
> I'm getting errors of hashtable already destroyed when running
> phpMyAdmin with PHP 5.3, and (of course), thinking this is a phar  
> issue,
> I've traced through and found a problem in the shutdown order.
> Basically, php_request_shutdown() calls zend_deactivate() which calls
> zend_destroy_rsrc_list(&EG(regular_list)).  On the next line,
> zend_post_deactivate_modules() is called, which steps through the  
> module
> list and unloads all the dynamically loaded modules.  If one of these
> modules (like mysqli) declares a resource type, then in
> module_destructor() zend_clean_module_rsrc_dtors() is called, which
> calls zend_clean_modules_rsrc_dtors_cb() (zend_list.c:253).
>
> This function then walks over EG(regular_list), which had been
> previously destroyed.
>
> I think this issue could be fixed by moving the
> zend_destroy_rsrc_list(&EG(regular_list)) call after the module
> shutdown.  I've attached a patch demonstrating the principle (this  
> fixes
> the hashtable destroyed message and I don't get anything bad like a
> segfault).
>
> Could someone with more brains double-check this one?  I think it  
> can be
> reproduced with a debug build using mysqli loaded dynamically and any
> script that uses mysqli, but I've only reproduced it with phpMyAdmin.
>
> Thanks,
> Greg
> Index: Zend/zend.c
> ===================================================================
> RCS file: /repository/ZendEngine2/zend.c,v
> retrieving revision 1.308.2.12.2.35.2.18
> diff -u -r1.308.2.12.2.35.2.18 zend.c
> --- Zend/zend.c	29 Apr 2008 08:15:16 -0000	1.308.2.12.2.35.2.18
> +++ Zend/zend.c	16 Jun 2008 02:53:00 -0000
> @@ -901,7 +901,8 @@
> 		shutdown_compiler(TSRMLS_C);
> 	} zend_end_try();
>
> -	zend_destroy_rsrc_list(&EG(regular_list) TSRMLS_CC);
> +	/* shutdown order issue */
> +	/* zend_destroy_rsrc_list(&EG(regular_list) TSRMLS_CC); */
>
> #ifdef ZEND_DEBUG
> 	if (GC_G(gc_enabled) && !CG(unclean_shutdown)) {
> Index: main/main.c
> ===================================================================
> RCS file: /repository/php-src/main/main.c,v
> retrieving revision 1.640.2.23.2.57.2.22
> diff -u -r1.640.2.23.2.57.2.22 main.c
> --- main/main.c	21 May 2008 15:55:31 -0000	1.640.2.23.2.57.2.22
> +++ main/main.c	16 Jun 2008 02:53:02 -0000
> @@ -1527,6 +1527,8 @@
> 		zend_post_deactivate_modules(TSRMLS_C);
> 	} zend_end_try();
>
> +	zend_destroy_rsrc_list(&EG(regular_list) TSRMLS_CC);
> +
> 	/* 9. SAPI related shutdown (free stuff) */
> 	zend_try {
> 		sapi_deactivate(TSRMLS_C);
>
> -- 
> PHP Internals - PHP Runtime Development Mailing List
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Lukas Kahwe Smith
mls@pooteeweet.org