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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/1400/">https://reviewboard.asterisk.org/r/1400/</a>
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<p style="margin-top: 0;">On August 30th, 2011, 4:38 a.m., <b>Alec Davis</b> wrote:</p>
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<a href="https://reviewboard.asterisk.org/r/1400/diff/1/?file=19855#file19855line2836" 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_hangup(struct ast_channel *chan)</pre></td>
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<td bgcolor="#c5ffc4" 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="n">chan</span><span class="p">,</span> <span class="n">AST_FLAG_ZOMBIE</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;">should setting a channel to a ZOMBIE also be done in features.c:set_kill_chan_tech(... ) and any where else before chan->tech->hangup(chan) is called?</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;">No. The ZOMBIE flag indicates the channel is dead. It just hasn't been buried yet. The set_kill_chan_tech() is replacing the channel technology not actually hanging up the channel.
This question has indicated that chan_agent is doing something with the ZOMBIE flag that is no longer going to work with this patch.</pre>
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<p>- rmudgett</p>
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<p>On August 29th, 2011, 6:51 p.m., rmudgett wrote:</p>
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<div>Review request for Asterisk Developers, Alec Davis and irroot.</div>
<div>By rmudgett.</div>
<p style="color: grey;"><i>Updated Aug. 29, 2011, 6:51 p.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;">Attempting to pickup a call that has been forked to multiple extensions by two users either crashes or fails a masquerade with a "bad things may happen" message.
This is the scenario that is causing all the grief:
1) Pickup target is selected
2) target is marked as being picked up in ast_do_pickup()
3) target is unlocked by ast_do_pickup()
4) app dial or queue gets a chance to hang up losing calls and calls ast_hangup() on target
5) SINCE A MASQUERADE HAS NOT BEEN SETUP YET BY ast_do_pickup() with ast_channel_masquerade(), ast_hangup() completes successfully and the channel is no longer in the channels container.
6) ast_do_pickup() then calls ast_channel_masquerade() to schedule the masquerade on the dead channel.
7) ast_do_pickup() then calls ast_do_masquerade() on the dead channel
8) bad things happen while doing the masquerade and in the process ast_do_masquerade() puts the dead channel back into the channels container
9) The "orphaned" channel is visible in the channels list if a crash does not happen.
This patch does the following:
1) ast_hangup() sets the zombie flag on a successfully hung-up channel and does not release the channel lock until that has happened.
2) __ast_channel_masquerade() is fixed to not setup a masquerade if either channel is a zombie.
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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;">Replicated the crash in ASTERISK-18222 with PickupChan() and *8 methods.
With the patch, the crash no longer happens and the new message of attempting to masquerade into a dead channel is output.</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-18222">ASTERISK-18222</a>,
<a href="https://issues.asterisk.org/jira/browse/ASTERISK-18273">ASTERISK-18273</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/main/channel.c <span style="color: grey">(333893)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/1400/diff/" style="margin-left: 3em;">View Diff</a></p>
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