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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/1373/">https://reviewboard.asterisk.org/r/1373/</a>
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<a href="https://reviewboard.asterisk.org/r/1373/diff/2/?file=18508#file18508line25659" style="color: black; font-weight: bold; text-decoration: underline;">./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 sip_send_mwi_to_peer(struct sip_peer *peer, int cache_only)</pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <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="p">}</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="cm">/* We have multiple threads (mwi events and monitor retransmits) working with this PVT and as we modify the sip history if that's turned on,</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="cm"> we really need to have a lock on it */</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">sip_pvt_lock</span><span class="p">(</span><span class="n">p</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="cm">/* Send MWI */</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="cm">/* Send MWI */</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">ast_set_flag</span><span class="p">(</span><span class="o">&</span><span class="n">p</span><span class="o">-></span><span class="n">flags</span><span class="p">[</span><span class="mi">0</span><span class="p">],</span> <span class="n">SIP_OUTGOING</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">ast_set_flag</span><span class="p">(</span><span class="o">&</span><span class="n">p</span><span class="o">-></span><span class="n">flags</span><span class="p">[</span><span class="mi">0</span><span class="p">],</span> <span class="n">SIP_OUTGOING</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="cm">/* the following will decrement the refcount on p as it finishes */</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="cm">/* the following will decrement the refcount on p as it finishes */</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">transmit_notify_with_mwi</span><span class="p">(</span><span class="n">p</span><span class="p">,</span> <span class="n">newmsgs</span><span class="p">,</span> <span class="n">oldmsgs</span><span class="p">,</span> <span class="n">peer</span><span class="o">-></span><span class="n">vmexten</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">transmit_notify_with_mwi</span><span class="p">(</span><span class="n">p</span><span class="p">,</span> <span class="n">newmsgs</span><span class="p">,</span> <span class="n">oldmsgs</span><span class="p">,</span> <span class="n">peer</span><span class="o">-></span><span class="n">vmexten</span><span class="p">);</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">sip_pvt_unlock</span><span class="p">(</span><span class="n">p</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">dialog_unref</span><span class="p">(</span><span class="n">p</span><span class="p">,</span> <span class="s">"unref dialog ptr p just before it goes out of scope at the end of sip_send_mwi_to_peer."</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">dialog_unref</span><span class="p">(</span><span class="n">p</span><span class="p">,</span> <span class="s">"unref dialog ptr p just before it goes out of scope at the end of sip_send_mwi_to_peer."</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="k">return</span> <span class="mi">0</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="k">return</span> <span class="mi">0</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;">What is the established locking order between peers and sip_pvts? The peer is locked during this function.</pre>
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<p>- David</p>
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<p>On August 18th, 2011, 7:15 a.m., Olle E Johansson wrote:</p>
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<div>Review request for Asterisk Developers.</div>
<div>By Olle E Johansson.</div>
<p style="color: grey;"><i>Updated Aug. 18, 2011, 7:15 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;">Historically, mwi was sent by one thread (monitor) and did not need any locking. With the addition of event driven MWI, we now have two threads, the event thread and the monitor thread for retransmits, that work on the same pvt. We have had multiple crashes in 1.6.0 caused by fights over the sip history linked list and memory corruption when removing entries (when the list overflows). Looking at it, we realized that no locking was done so the two threads where allowed to have fun with the same pvt at the same time.
This affects everything since the historic day we released 1.6.0</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;">Compiled fine. Felt fine. Under testing now.</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-18288">asterisk-18288</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">(332444)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/1373/diff/" style="margin-left: 3em;">View Diff</a></p>
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