<div dir="ltr">Hi, Thanks for reading my bug! I think this patch can not fix this problem now, because pipe2() requires Python 3.3.<br></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Jun 5, 2014 at 6:17 PM, laserjetyang <span dir="ltr"><<a href="mailto:laserjetyang@gmail.com" target="_blank">laserjetyang@gmail.com</a>></span> wrote:<br>
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<table width="550"><tbody><tr><td>Will this patch of Python fix your problem? <b><a href="http://bugs.python.org/issue7213" target="_blank">http://bugs.python.org/issue7213</a></b>
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<div class="gmail_quote">On Wed, Jun 4, 2014 at 10:41 PM, Qin Zhao <span dir="ltr"><<a href="mailto:chaochin@gmail.com" target="_blank">chaochin@gmail.com</a>></span> wrote:<br>
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<div>Hi Zhu Zhu,<br><br></div>Thank you for reading my diagram! I need to clarify that this problem does not occur during data injection. Before creating the ISO, the driver code will extend the disk. Libguestfs is invoked in that time frame.<br>
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<div>And now I think this problem may occur at any time, if the code use tpool to invoke libguestfs, and one external commend is executed in another green thread simultaneously. Please correct me if I am wrong.<br><br></div>
<div>I think one simple solution for this issue is to call libguestfs routine in greenthread, rather than another native thread. But it will impact the performance very much. So I do not think that is an acceptable solution.<br>
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<div>On Wed, Jun 4, 2014 at 12:00 PM, Zhu Zhu <span dir="ltr"><<a href="mailto:bjzzu.zz@gmail.com" target="_blank">bjzzu.zz@gmail.com</a>></span> wrote:<br></div></div>
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<div><span></span>Hi Qin Zhao,</div>
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<div><span style="LINE-HEIGHT:1.5;BACKGROUND-COLOR:window;FONT-SIZE:10.5pt">Thanks for raising this issue and analysis. </span>According to the issue description and happen scenario(<a style="LINE-HEIGHT:1.5;BACKGROUND-COLOR:window;FONT-SIZE:10.5pt" href="https://docs.google.com/drawings/d/1pItX9urLd6fmjws3BVovXQvRg_qMdTHS-0JhYfSkkVc/pub?w=960&h=720" target="_blank">https://docs.google.com/drawings/d/1pItX9urLd6fmjws3BVovXQvRg_qMdTHS-0JhYfSkkVc/pub?w=960&h=720</a>)<span style="LINE-HEIGHT:1.5;BACKGROUND-COLOR:window;FONT-SIZE:10.5pt">, </span><span style="LINE-HEIGHT:1.5;BACKGROUND-COLOR:window;FONT-SIZE:10.5pt">if that's the case, concurrent mutiple KVM spawn instances(</span><b style="LINE-HEIGHT:1.5;FONT-SIZE:10.5pt">with both config drive and data injection enabled</b><span style="LINE-HEIGHT:1.5;BACKGROUND-COLOR:window;FONT-SIZE:10.5pt">) are triggered, the issue can be very likely to happen. </span></div>
<div>As in libvirt/driver.py <span style="LINE-HEIGHT:1.5;FONT-SIZE:10.5pt">_create_image method</span><span style="LINE-HEIGHT:1.5;BACKGROUND-COLOR:window;FONT-SIZE:10.5pt">, right after iso making "</span><span style="LINE-HEIGHT:1.5;FONT-SIZE:10.5pt">cdb.make_drive", the driver will attempt "data injection" which will call the libguestfs launch in another thread. </span></div>
<div><span style="LINE-HEIGHT:1.5;BACKGROUND-COLOR:window;FONT-SIZE:10.5pt"><br></span></div>
<div><span style="LINE-HEIGHT:1.5;BACKGROUND-COLOR:window;FONT-SIZE:10.5pt">Looks there were also a couple of libguestfs hang issues from Launch pad as below. . I am not sure if libguestfs itself can have certain mechanism to free/close the fds that inherited from parent process instead of require explicitly calling the tear down. Maybe open a defect to libguestfs to see what their thoughts? </span></div>
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<div><span><a href="https://bugs.launchpad.net/nova/+bug/1286256" target="_blank">https://bugs.launchpad.net/nova/+bug/1286256</a></span></div><span></span></div>
<div><a style="LINE-HEIGHT:1.5;BACKGROUND-COLOR:window;FONT-SIZE:10.5pt" href="https://bugs.launchpad.net/nova/+bug/1270304" target="_blank">https://bugs.launchpad.net/nova/+bug/1270304</a><span style="LINE-HEIGHT:1.5;FONT-SIZE:10.5pt"> </span></div>
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<div>Zhu Zhu</div>
<div>Best Regards</div></div></span></div>
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<div><b>From:</b> <a href="mailto:chaochin@gmail.com" target="_blank">Qin Zhao</a></div>
<div><b>Date:</b> <a href="tel:2014-05-31%C2%A001" value="+12014053101" target="_blank">2014-05-31 01</a>:25</div>
<div>
<div><b>To:</b> <a href="mailto:openstack-dev@lists.openstack.org" target="_blank">OpenStack Development Mailing List (not for usage questions)</a></div>
<div><b>Subject:</b> [openstack-dev] [Nova] nova-compute deadlock</div></div></div></div>
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<div>Hi all,<br><br></div>When I run Icehouse code, I encountered a strange problem. The nova-compute service becomes stuck, when I boot instances. I report this bug in <a href="https://bugs.launchpad.net/nova/+bug/1313477" target="_blank">https://bugs.launchpad.net/nova/+bug/1313477</a>.<br>
<br></div>After thinking several days, I feel I know its root cause. This bug should be a deadlock problem cause by pipe fd leaking. I draw a diagram to illustrate this problem. <a href="https://docs.google.com/drawings/d/1pItX9urLd6fmjws3BVovXQvRg_qMdTHS-0JhYfSkkVc/pub?w=960&h=720" target="_blank">https://docs.google.com/drawings/d/1pItX9urLd6fmjws3BVovXQvRg_qMdTHS-0JhYfSkkVc/pub?w=960&h=720</a><br clear="all">
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<div>However, I have not find a very good solution to prevent this deadlock. This problem is related with Python runtime, libguestfs, and eventlet. The situation is a little complicated. Is there any expert who can help me to look for a solution? I will appreciate for your help!<br>
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<div><br>-- <br>
<div dir="ltr">Qin Zhao<br></div></div></div></div></div></div></div></div></div></div></div></blockquote></div><br></div></div>_______________________________________________<br>OpenStack-dev mailing list<br><a href="mailto:OpenStack-dev@lists.openstack.org" target="_blank">OpenStack-dev@lists.openstack.org</a><br>
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<br clear="all"><br>-- <br>
<div dir="ltr">Qin Zhao<br></div></font></span></div><br>_______________________________________________<br>OpenStack-dev mailing list<br><a href="mailto:OpenStack-dev@lists.openstack.org" target="_blank">OpenStack-dev@lists.openstack.org</a><br>
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<br></blockquote></div><br><br clear="all"><br>-- <br><div dir="ltr">Qin Zhao<br></div>
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