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<p class="MsoNormal">Package: slapd<o:p></o:p></p>
<p class="MsoNormal">Version: 2.4.31-2+deb7u2<o:p></o:p></p>
<p class="MsoNormal"><span style="color:black">+X-Debbugs-CC: ryan@openldap.org<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Greetings,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I've noticed that sometimes the "slapd" fails to stop. I can reproduce the problem only on machines with multiple cores (more than 2) when there are many<o:p></o:p></p>
<p class="MsoNormal">concurrent connections and the server is under a heavy "stress" .<o:p></o:p></p>
<p class="MsoNormal">Note that I tried the current standard version (2.4.31-deb7u2) as well as the wheezy-backports - 2.4.31+really2.4.40+dfsg-1+deb8u1~bpo70+1 .<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In the logs i was able to identify the first "shutdown" log:<o:p></o:p></p>
<p class="MsoNormal"> daemon: shutdown requested and initiated<o:p></o:p></p>
<p class="MsoNormal">However the next expected shutdown logs are missing ("waiting for ...operations/tasks to finish" and "slapd stopped") .
<o:p></o:p></p>
<p class="MsoNormal">Hence, i believe that it's related to closing the sockets/listeners (this is my guess based on the source code, however i never debugged/proved it).<o:p></o:p></p>
<p class="MsoNormal">Please note that i'm using virtual environment so i was able to reproduce it only when i used more than 4 cores.<o:p></o:p></p>
<p class="MsoNormal">Also please note that my system is a customized (hardened) Debian wheezy (7.9) and I built the slapd from the Debian sources (apt-get source …) .<o:p></o:p></p>
<p class="MsoNormal">I REALLY (!!) hope that this is valid bug since I’m surprised that I’m the only one who encountered this situation.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">How to reproduced it:<o:p></o:p></p>
<p class="MsoNormal">-------------------------------<o:p></o:p></p>
<p class="MsoNormal">I guess that there are a few ways to reproduce it , I managed to easily reproduce it with two terminates – one producing “ldapsearch” stress and the other restarting slapd :<o:p></o:p></p>
<p class="MsoNormal">- Open two terminals.<o:p></o:p></p>
<p class="MsoNormal">- On terminal #1 i'm just manually running "slapd restart" commands:<o:p></o:p></p>
<p class="MsoNormal"> # /etc/init.d/slapd status ; /etc/init.d/slapd restart<o:p></o:p></p>
<p class="MsoNormal">- On terminal #2 i'm running a infinite loops of simple "ldapsearch" (100<o:p></o:p></p>
<p class="MsoNormal">concurrent processes running loops of ldapsearch). Terminal #2 is trying to<o:p></o:p></p>
<p class="MsoNormal">simulate many concurrent read operations. see "more information" later for the<o:p></o:p></p>
<p class="MsoNormal">exact scripts that i used.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Incorrect behavior:<o:p></o:p></p>
<p class="MsoNormal">-------------------------<o:p></o:p></p>
<p class="MsoNormal">The "slapd restart" works a few times, and then the "stop" operation fails.<o:p></o:p></p>
<p class="MsoNormal">The stop continues to fail even if i stop all "stress" and terminate all<o:p></o:p></p>
<p class="MsoNormal">ldapsearch/connections (CPU is 99% idle !)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Expected Behavior:<o:p></o:p></p>
<p class="MsoNormal">-------------------------<o:p></o:p></p>
<p class="MsoNormal">All slapd stop/restart operations complete successfully <o:p>
</o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">More Information (optional – my exact scripts):<o:p></o:p></p>
<p class="MsoNormal">----------------------------------------------------------------<o:p></o:p></p>
<p class="MsoNormal">On terminal#2 i used a very simple script to generate a "read only" stress:<o:p></o:p></p>
<p class="MsoNormal"># cat > ldaploop.sh << EOF<o:p></o:p></p>
<p class="MsoNormal">#!/bin/sh<o:p></o:p></p>
<p class="MsoNormal">while true ; do ldapsearch -x -Z ; done<o:p></o:p></p>
<p class="MsoNormal">EOF<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"># cat > manyloops.sh << "EOF"<o:p></o:p></p>
<p class="MsoNormal">#!/bin/sh<o:p></o:p></p>
<p class="MsoNormal">for i in `seq 1 100` ; do ( ./ldaploop.sh &) ; done<o:p></o:p></p>
<p class="MsoNormal">EOF<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">As previously mentioned, i ran the "manyloops.sh" to generate 100 running<o:p></o:p></p>
<p class="MsoNormal">processes where each one simply runs "ldapsearch" (locally).<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">thanks in advance,<o:p></o:p></p>
<p class="MsoNormal">Zvika Ferentz<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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