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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/1118/">https://reviewboard.asterisk.org/r/1118/</a>
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<p style="margin-top: 0;">On May 26th, 2011, noon, <b>rmudgett</b> wrote:</p>
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<a href="https://reviewboard.asterisk.org/r/1118/diff/7/?file=16740#file16740line6445" style="color: black; font-weight: bold; text-decoration: underline;">/trunk/main/channel.c</a>
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(Diff revision 7)
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">int ast_do_masquerade(struct ast_channel *original)</pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="cm">/* lock the original channel to determine if the masquerade is require or not */</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="cm">/* lock the original channel<span class="hl"> with deadlock avoidance</span> to determine if the masquerade is require or not */</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">ast_channel_lock</span><span class="p">(</span><span class="n">original</span><span class="p">)<span class="hl">;</span></span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="hl"> </span><span class="k"><span class="hl">while</span></span><span class="hl"> </span><span class="p"><span class="hl">(</span></span><span class="n">ast_channel_<span class="hl">try</span>lock</span><span class="p">(</span><span class="n">original</span><span class="p">)<span class="hl">)</span></span><span class="hl"> </span><span class="p"><span class="hl">{</span></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">ao2_unlock</span><span class="p">(</span><span class="n">channels</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">usleep</span><span class="p">(</span><span class="mi">1</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">ao2_lock</span><span class="p">(</span><span class="n">channels</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="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;">The defined locking order is the channels container then the channel. This is not the correct way to fix the deadlock.</pre>
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<p>On May 26th, 2011, 12:17 p.m., <b>rmudgett</b> wrote:</p>
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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;">Is the original deadlock still possible?</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;">i will put a log message on if you want and try catch it ...
i have seen this regualarly under the following circumstances
ring all group 5+ phones not attended in evenings simultaneous pickups triggered ...
ast_channel_masquerade is called with channel locked it should not be ...
/*!
* \brief Masquerade a channel
*
* \note Assumes _NO_ channels and _NO_ channel pvt's are locked. If a channel is locked while calling
* this function, it invalidates our channel container locking order. All channels
* must be unlocked before it is permissible to lock the channels' ao2 container.
*/
now with ao2_callback_find locking and unlocking channels and channels this deadlock is possible AFAIK
the recent changes did not sort out this possible problem due to it been locked going in...</pre>
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<p>- irroot</p>
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<p>On May 26th, 2011, 3:58 a.m., irroot wrote:</p>
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<div>Review request for Asterisk Developers.</div>
<div>By irroot.</div>
<p style="color: grey;"><i>Updated 2011-05-26 03:58:55</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;">as a companion to 0018825 to aid with the move from call-limits to channel group variables. the problem with pickup and queue is that they manage channels outside the dialplan and need "helpers" to deal with channel groups.
in the case of pickup when a call is placed to a extension with say a "<EXTEN>@called" channel group when it is picked up this needs to be cleared to allow further calls when call waiting is disabled.
exten => s,n,GotoIf($[$[${ GROUP_COUNT(${ARG1}@called)} >= 1] | $[${GROUP_COUNT(${ARG1}@caller)} >= 1] | $[${GROUP_COUNT(${ARG1}@pickup)} >= 1] | $[${GROUP_COUNT(${ARG1}@qagent)} >= 1]]?s-BUSY,1)
where
caller is set when a call is placed.
called is set when a call is received
pickup is set when before calling pickup in the dialplan
qagent is set with patch to queue
Hope this is found to be useful and finds a home in trunk.
not sure what time to put in the "wait for bridge" perhaps there is a better method ?? </pre>
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<b style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Bugs: </b>
<a href="https://issues.asterisk.org/view.php?id=18830">18830</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/apps/app_directed_pickup.c <span style="color: grey">(320772)</span></li>
<li>/trunk/main/channel.c <span style="color: grey">(320772)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/1118/diff/" style="margin-left: 3em;">View Diff</a></p>
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