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Date: Fri, 26 Jan 2018 12:43:15 +0100
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Subject: threadsafe php crashes too easily
From: Hajo.Locke@gmx.de (Hajo Locke)

Hello List,

i hope this is the right place to get helped. I have a promising setup 
for testing purposes, but unfortunately i ran quick into problems.

  I compiled a minimal libphp7.so (7.2.1)  using this line:
./configure --disable-all  --enable-static --prefix=/usr 
--with-apxs2=/usr/bin/apxs2 --enable-maintainer-zts

I enabled threadsafety to use this libphp7.so in apache 2.4 with a 
threaded mpm like worker or event. the plan is to just load it with 
LoadModule in apache but not to use it.
the real php-processing is done by a fastcgi-setup in apache using 
php-fpm (not needed to reproduce error). the idea is to support 
php_value/php_flag etc. in .htaccess files for my users even if they use 
a fastcgi-setup. all i need is htscanner extension for php-cgi and just 
a loaded libphpx.so to register these directives in apache. may be this 
is a dump idea, but i have thousands of users who use libphpx.so and a 
huge number of .htaccess with php_value/php_flag directives. currently i 
see no possibility to tell users to switch to .user.ini

First steps are really successful and all worked well. Even benchmarking 
the system with massrequests did not show any error. php_value/php_flag 
in .htaccess showed expected behaviour when requesting a php-file using 
fastcgi.
Unfortunately there is only a small change to see lots of segfaults in 
errorlog: Just enable a php_value directive in VHost-Config for this 
particular VHost along with a php_value directive in .htaccess in 
docroot of this VHost. It is not needed to request a php-file, just 
requesting a small static file is enough. The smaller the requested file 
and higher requests per second the higher is count of segfaults.

I knew that threadsafe-compiled php is a problematic thing and recommend 
mpm is prefork when not using a fastcgi-configuration, but iam surprised 
that i see the crashes so easily. I used a minimal php and it seems 
problem occurs just by reading and applying the values set by php_value 
for particular request.

Do i have a chance to get this setup safe?

Thanks a lot,
Hajo