title: php-fpm forever respawning children when executing uglifycss
body: <p>I have such line in a php application:</p>
  
  <pre><code>exec('uglifycss 1.css 2.css &gt; main.css');
  </code></pre>
  
  <p>After executing it, php-fpm starts to restart all children non stopping, which leads to 100% cpu on a server in seconds. Only service php-fpm restart saves the situation. All other parts of app work well and exec with other commands (uglifyjs, ssconvert, wkhtmltopdf) work well, only this line causes such troubles.</p>
  
  <p>Executing <code>uglifycss</code> in bash works well, disabling opcache does not help, all the permissions are correct, changing uglifycss version does not help. The line itself works well - minified file appears in a folder.</p>
  
  <p>Php-fpm logs:</p>
  
  <pre><code>[07-Jun-2017 00:10:39] NOTICE: fpm is running, pid 21162
  [07-Jun-2017 00:10:39] NOTICE: ready to handle connections
  [07-Jun-2017 00:10:39] NOTICE: systemd monitor interval set to 10000ms
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21199 exited with code 0 after 0.011741 seconds from start
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21200 started
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21200 exited with code 0 after 0.012848 seconds from start
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21201 started
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21201 exited with code 0 after 0.011070 seconds from start
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21202 started
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21202 exited with code 0 after 0.012875 seconds from start
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21203 started
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21203 exited with code 0 after 0.012139 seconds from start
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21204 started
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21204 exited with code 0 after 0.012334 seconds from start
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21205 started
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21205 exited with code 0 after 0.011729 seconds from start
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21206 started
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21206 exited with code 0 after 0.010936 seconds from start
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21207 started
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21207 exited with code 0 after 0.011194 seconds from start
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21208 started
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21208 exited with code 0 after 0.011382 seconds from start
  [07-Jun-2017 00:10:59] NOTICE: [pool app] child 21209 started
  </code></pre>
  
  <p>and so on until service won't be manually restarted...</p>
  
  <p>Server info:</p>
  
  <pre><code>CentOS 7, php 7.1.5, node 8.0.0, npm 5.0.0, uglifycss 0.0.27
  </code></pre>
  
  <p>Seems like a bug, does anyone have the same issue? Is there any fix to this?</p>