Wait, I can test everything, but which method should I use (to disable Zend Memory Manager)? The crashes occur even in 5.3-latest, so please tell me what should I *exactly* do with this snapshot.

How about you tell us what the crash is you get? (what bug id was the one you reported?) Also note that some crash bugs were fixed recently.
And there are no -disable-zend-memory-manager or --enable-malloc-mm configure options. To disable the memory manager (for debugging) you start e.g. apache with same way you do with PHP CLI:

# USE_ZEND_ALLOC=0 /usr/sbin/httpd <your options here>

So the bug I referred to was http://bugs.php.net/bug.php?id=43397. Curently it's marked as a duplicate of some other bug, which is now closed because of lack of feedback. I tried to request reopening my original bug, unfortunately without success.

About setting env var - please note that I tried this method. No go. phpinfo shows that Zend Memory Manager is enabled. Note that I didn't set it from command line, but had in environment (something like export USE_ZEND_ALLOC=0; /usr/sbin/httpd ...). But it shouldn't make a difference.

Well, reproduction script is *not*needed* as it's a PHP configuration setting issue. It is visible for example in <? phpinfo(); ?> and I gave exact *steps* to reproduce at the beginning.

Here they are, for convenience:

The goal is to disable the Zend Memory Manager.

Try #1:

1. set USE_ZEND_ALLOC in the environment (/etc/profile)
1a. also tried other ways, like setting it in the Apache config (SetEnv etc)
2. Restart Apache to make sure change takes effect
3. View phpinfo page to see if Zend Memory Manager got disabled
3a. But this way works for the CLI version of PHP (setting env in /etc/profile).

Try #2:
(proven to be futile and ineffective, but anyway)

I tried to recompile PHP with ./configure switches like --disable-zend-memory-manager or --enable-malloc-mm (some webpages told they will disable Zend MM), but as other developers said in this report, there are no such compile options.

How about --disable-malloc-mm ??

After compiling with that option Zend MM is still enabled, according to phpinfo().

Anyway, it must be possible to somehow disable it, because debug build does it. But it would be not a good solution to use debug build in production.

Please, please check it yourself, *seriously* - no guessing, not requiring me to check every opportunity.

Works fine here. What SAPI are you using?

/usr/share/nginx/html$ USE_ZEND_ALLOC=0 PHP_FCGI_CHILDREN=0 php-cgi -b 0:9999

$ curl --progress localhost/info.php | grep "Memory Manager" 

<tr><td class="e">Zend Memory Manager </td><td class="v">disabled </td></tr>

It's really just coming from the environment:
http://lxr.php.net/xref/PHP_TRUNK/Zend/zend_alloc.c#2723

No feedback was provided. The bug is being suspended because
we assume that you are no longer experiencing the problem.
If this is not the case and you are able to provide the
information that was requested earlier, please do so and
change the status of the bug back to "Re-Opened". Thank you.

I had a similar problem with Apache 2.2 and PHP 5.4.30.deb and Zend Engine 2.4.0.

I found putting:
EXPORT USE_ZEND_ALLOC=0

in my /etc/apache/envvars solved the issue for me. All other methods would get the php command line version to work, but not through apache mod_php.

Hope this helps someone.