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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/1564/">https://reviewboard.asterisk.org/r/1564/</a>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">sip_subscribe_mwi_sip_destroy is still directly destroying the dialog related to the sip_subscription_mwi. I have a feeling that will do some interesting things, and may be good to snag as well with this patch, since you're influencing how sip dialogs are destroyed.</pre>
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<a href="https://reviewboard.asterisk.org/r/1564/diff/1/?file=21604#file21604line29970" style="color: black; font-weight: bold; text-decoration: underline;">/branches/1.8/channels/chan_sip.c</a>
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(Diff revision 1)
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static int unload_module(void)</pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">ao2_t_ref</span><span class="p">(</span><span class="n">dialogs_needdestroy</span><span class="p">,</span> <span class="o">-</span><span class="mi">1</span><span class="p">,</span> <span class="s">"unref the dialogs table"</span><span class="p">);</span></pre></td>
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<pre style="margin-left: 2em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">This should be 'dialogs_needdestroy' in the comment</pre>
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<p>- mjordan</p>
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<p>On November 3rd, 2011, 3:14 p.m., rmudgett wrote:</p>
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<div>Review request for Asterisk Developers, David Vossel and schmidts.</div>
<div>By rmudgett.</div>
<p style="color: grey;"><i>Updated Nov. 3, 2011, 3:14 p.m.</i></p>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Timing between dialog destruction and a MWI event sending a message could result in a deadlock.
Order of events causing deadlock:
1a) The event subscription system calls the registered callbacks with its list RWLOCK held.
1b) The SIP monitor checks for dialogs needing destruction. It does an ao2_callback that holds the dialogs container lock while searching for dialogs to destroy.
2a) The event subscription SIP callback needs to create a temporary dialog to send out the MWI notification. That temporary dialog needs to be inserted in the dialogs container so it must wait.
2b) The dialog search finds a dialog to destroy and as a result releases the last reference for a peer. The peer destructor attempts to get the subscription RWLOCK but must wait.
3) deadlock
This is based off of the original diff posted for review: https://reviewboard.asterisk.org/r/1557/
It directly addresses the comment dvossel posted to the original diff of https://reviewboard.asterisk.org/r/1557/</pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">It compiles. :)</pre>
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<b style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Bugs: </b>
<a href="https://issues.asterisk.org/jira/browse/ASTERISK-18747">ASTERISK-18747</a>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>/branches/1.8/channels/chan_sip.c <span style="color: grey">(343338)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/1564/diff/" style="margin-left: 3em;">View Diff</a></p>
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