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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/2946/">https://reviewboard.asterisk.org/r/2946/</a>
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<a href="https://reviewboard.asterisk.org/r/2946/diff/1/?file=47360#file47360line349" style="color: black; font-weight: bold; text-decoration: underline;">branches/12/bridges/bridge_native_rtp.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 struct ast_frame *native_rtp_framehook(struct ast_channel *chan, struct ast_frame *f, enum ast_framehook_event event, void *data)</pre></td>
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<th bgcolor="#f0f0f0" style="border-right: 1px solid #C0C0C0;" align="right"><font size="2">349</font></th>
<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="k">if</span> <span class="p">(</span><span class="n">f</span><span class="o">-></span><span class="n">subclass</span><span class="p">.</span><span class="n">integer</span> <span class="o">==</span> <span class="n">AST_CONTROL_HOLD</span><span class="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="tb"> </span><span class="tb"> </span><span class="k">if</span> <span class="p">(</span><span class="n">f</span><span class="o">-></span><span class="n">subclass</span><span class="p">.</span><span class="n">integer</span> <span class="o">==</span> <span class="n">AST_CONTROL_HOLD</span><span class="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="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="n">native_rtp_bridge_stop</span><span class="p">(</span><span class="n">bridge</span><span class="p">,</span> <span class="n">chan</span><span class="p">,</span> <span class="nb">NULL</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="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="n">native_rtp_bridge_stop</span><span class="p">(</span><span class="n">bridge</span><span class="p">,</span> <span class="n">chan</span><span class="p">,</span> <span class="nb">NULL</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="tb"> </span><span class="tb"> </span><span class="p">}</span> <span class="k">else</span> <span class="k">if</span> <span class="p">((</span><span class="n">f</span><span class="o">-></span><span class="n">subclass</span><span class="p">.</span><span class="n">integer</span> <span class="o">==</span> <span class="n">AST_CONTROL_UNHOLD</span><span class="p">)</span> <span class="o">||</span> <span class="p">(</span><span class="n">f</span><span class="o">-></span><span class="n">subclass</span><span class="p">.</span><span class="n">integer</span> <span class="o">==</span> <span class="n">AST_CONTROL_UPDATE_RTP_PEER</span><span class="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="tb"> </span><span class="tb"> </span><span class="p">}</span> <span class="k">else</span> <span class="k">if</span> <span class="p">((</span><span class="n">f</span><span class="o">-></span><span class="n">subclass</span><span class="p">.</span><span class="n">integer</span> <span class="o">==</span> <span class="n">AST_CONTROL_UNHOLD</span><span class="p">)</span> <span class="o">||</span> <span class="p">(</span><span class="n">f</span><span class="o">-></span><span class="n">subclass</span><span class="p">.</span><span class="n">integer</span> <span class="o">==</span> <span class="n">AST_CONTROL_UPDATE_RTP_PEER</span><span class="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="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="n">native_rtp_bridge_start</span><span class="p">(</span><span class="n">bridge</span><span class="p">,</span> <span class="n">chan</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="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="n">native_rtp_bridge_start</span><span class="p">(</span><span class="n">bridge</span><span class="p">,</span> <span class="n">chan</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="tb"> </span><span class="tb"> </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="tb"> </span><span class="tb"> </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;">Calling the native_rtp_bridge_stop() and native_rtp_bridge_start() functions without the bridge locked is bad. You should never access the bridge channels list without the bridge locked.</pre>
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<a href="https://reviewboard.asterisk.org/r/2946/diff/1/?file=47361#file47361line506" style="color: black; font-weight: bold; text-decoration: underline;">branches/12/channels/chan_pjsip.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 chan_pjsip_set_rtp_peer(struct ast_channel *chan,</pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="k">struct</span> <span class="n">ast_channel</span> <span class="o">*</span><span class="n">bridge_peer</span><span class="p">;</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="n">SCOPED_CHANNELLOCK</span><span class="p">(</span><span class="n">chan_lock</span><span class="p">,</span> <span class="n">chan</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;">I think this is the wrong place to lock the channel. This function should be called with the channel already locked so other channel drivers will have similar locked environments in their versions of the function.
The function is called with the channel already locked on early media. The function is called by native_rtp_bridge_start()/native_rtp_bridge_stop() with the bridge locked but not the channel.</pre>
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<a href="https://reviewboard.asterisk.org/r/2946/diff/1/?file=47362#file47362line6873" style="color: black; font-weight: bold; text-decoration: underline;">branches/12/main/channel.c</a>
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">void ast_do_masquerade(struct ast_channel *original)</pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span>if ((bridged = ast_channel_bridge_peer(original))) {</pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span>if ((bridged = ast_channel_bridge_peer(original))) {</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;">Add the note
* \note Absolutely _NO_ channel locks should be held before calling this function.
to the ast_channel_bridge_peer() doxygen comment in channel.h.</pre>
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<p>- rmudgett</p>
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<p>On October 22nd, 2013, 3:21 p.m. UTC, opticron wrote:</p>
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<div>Review request for Asterisk Developers.</div>
<div>By opticron.</div>
<p style="color: grey;"><i>Updated Oct. 22, 2013, 3:21 p.m.</i></p>
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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-22628">ASTERISK-22628</a>
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<b style="color: #575012; font-size: 10pt;">Repository: </b>
Asterisk
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<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;">This corrects two locking inversions between channels and bridges. The proper locking order is bridge -> bridge_channel -> channel.
The instance in ast_do_masquerade is easy enough to spot and fix.
The other instance involves framehooks which are always called with the channel locked and must not be unlocked, a native RTP bridge setup, and a chan_pjsip channel tech callback that attempts to lock a channel's associated bridge. Fortunately, it is not actually necessary to lock the bridge in question and reach across to find the bridged peer since a check to see if the associated bridge exists will do just as well.
This also cleans up some unnecessary locking in bridge_native_rtp.c.</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;">This resolves a deadlock that sometimes occurs when attempting to create a 4-way call via attended transfers.</pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>branches/12/bridges/bridge_native_rtp.c <span style="color: grey">(401310)</span></li>
<li>branches/12/channels/chan_pjsip.c <span style="color: grey">(401310)</span></li>
<li>branches/12/main/channel.c <span style="color: grey">(401310)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/2946/diff/" style="margin-left: 3em;">View Diff</a></p>
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