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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/1224/">https://reviewboard.asterisk.org/r/1224/</a>
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<a href="https://reviewboard.asterisk.org/r/1224/diff/1/?file=16580#file16580line6463" style="color: black; font-weight: bold; text-decoration: underline;">/branches/1.8/main/channel.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; ">int ast_do_masquerade(struct ast_channel *original)</pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="cm">/*</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 just hung up the physical side of the channel. Set the</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"> * new zombie to use the null channel driver for safety.</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"> */</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">clonechan</span><span class="o">-></span><span class="n">tech</span> <span class="o">=</span> <span class="o">&</span><span class="n">ast_null_tech</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">/* Mangle the name of the clone channel */</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">/* Mangle the name of the clone channel */</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 all makes perfect sense to me. We are essentially disconnecting the tech_pvt before calling hangup on the channel. Once the tech_pvt is told to disconnect we should never call back into that technology, but we can not guarantee this will not happen because the channel hasn't actually been hung up. This is why we have all those checks to the AST_FLAG_ZOMBIE before calling a channel tech's function.
This can be thought of as a catch all for all the times we would have to check the AST_FLAG_ZOMBIE flag.</pre>
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<p>- David</p>
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<p>On May 20th, 2011, 12:22 p.m., rmudgett wrote:</p>
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<div>Review request for Asterisk Developers, Russell Bryant and David Vossel.</div>
<div>By rmudgett.</div>
<p style="color: grey;"><i>Updated 2011-05-20 12:22:12</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;">Recent crashes from zombie channels suggests that they need a safe home to goto.
When a masquerade happens, the physical part of the zombie channel is hungup. The hangup normally sets the channel private pointer to NULL. If someone then blindly does a callback to the channel driver, a crash is likely because the private pointer is NULL.
The masquerade now sets the channel technology of zombie channels to the NULL channel driver.</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;">Tested a version of this patch without the zombie check committed for issue 19116. The crash was avoided.</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=19116">19116</a>,
<a href="https://issues.asterisk.org/view.php?id=19310">19310</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/include/asterisk/channel.h <span style="color: grey">(320060)</span></li>
<li>/branches/1.8/main/channel.c <span style="color: grey">(320060)</span></li>
<li>/branches/1.8/main/features.c <span style="color: grey">(320060)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/1224/diff/" style="margin-left: 3em;">View Diff</a></p>
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