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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/1563/">https://reviewboard.asterisk.org/r/1563/</a>
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<p style="margin-top: 0;">On November 4th, 2011, 12:35 p.m., <b>mjordan</b> wrote:</p>
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<a href="https://reviewboard.asterisk.org/r/1563/diff/2/?file=21625#file21625line24933" style="color: black; font-weight: bold; text-decoration: underline;">trunk/channels/chan_sip.c</a>
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(Diff revision 2)
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req, struct ast_sockaddr *addr, int seqno, const char *e)</pre></td>
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<th bgcolor="#f0f0f0" style="border-right: 1px solid #C0C0C0;" align="right"><font size="2">24924</font></th>
<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">add_peer_mwi_subs</span><span class="p">(</span><span class="n">authpeer</span><span class="p">);</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">add_peer_mwi_subs</span><span class="p">(</span><span class="n">authpeer</span><span class="p">);</span></pre></td>
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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;">Again, I'm confused why the sip_pvt needs to be unlocked / locked here, since add_peer_mwi_subs doesn't affect it.</pre>
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<pre style="margin-left: 1em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">add_peer_mwi_subs holds the global event lock when adding the subscription. If we hold the sip_pvt lock during this operation we are establishing that the global event lock is held after the sip_pvt.
The mwi_event_cb callback function occurs with the global event lock held, but during this function the sip_pvt lock is held. This would reverse the locking order if we did not unlock the sip_pvt when the event was being added.</pre>
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<p>- David</p>
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<p>On November 4th, 2011, 11:16 a.m., opticron wrote:</p>
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<div>Review request for Asterisk Developers and David Vossel.</div>
<div>By opticron.</div>
<p style="color: grey;"><i>Updated Nov. 4, 2011, 11:16 a.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;">Fix a locking inversion that causes deadlocks during BLF subscriptions.</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;">Compile</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-18663">ASTERISK-18663</a>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>trunk/channels/chan_sip.c <span style="color: grey">(342600)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/1563/diff/" style="margin-left: 3em;">View Diff</a></p>
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