[asterisk-dev] [Code Review] Fix a deadlock in agents occuring due to trying to lock a channel while having a lock on the pvt.

[Mark Michelson]

-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://reviewboard.asterisk.org/r/1708/#review5410
-----------------------------------------------------------

Ship it!


The potential deadlock I pointed out still exists between the channel and the list of agents, theoretically. The thing is, it's something that is much much much less likely to occur than the deadlock you are fixing because it requires the "pending" method of calling an agent. I'm not even sure if that is actually even documented anywhere. So for the purposes of doing what needed to be done here, this patch does the trick. Just fix up the unnecessary initializations Richard pointed out and it's good to go.

- Mark


On Feb. 3, 2012, 1:22 p.m., jrose wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviewboard.asterisk.org/r/1708/
> -----------------------------------------------------------
> 
> (Updated Feb. 3, 2012, 1:22 p.m.)
> 
> 
> Review request for Asterisk Developers, Mark Michelson, rmudgett, and Matt Jordan.
> 
> 
> Summary
> -------
> 
> Also adds locking to a number of other functions which are calling ast_bridged_channel (which is documented as requiring a lock for safe running, which was the purpose of irroot's original locking patch in action_agents.
> 
> Unlike the other patch on reviewboard right now, this opts to enforce locking order instead of using deadlock avoidance.
> 
> Celebrity endorsement: "This looks incredibly sane to me." - MMichelson
> 
> 
> This addresses bug ASTERISK-19285.
>     https://issues.asterisk.org/jira/browse/ASTERISK-19285
> 
> 
> Diffs
> -----
> 
>   /branches/1.8/channels/chan_agent.c 353685 
> 
> Diff: https://reviewboard.asterisk.org/r/1708/diff
> 
> 
> Testing
> -------
> 
> Not much I'm afraid to say. I can't reproduce the issue since it involves real world use over a period of time.  I'll ask Alex Villacís Lasso to give it a shot though.
> 
> 
> Thanks,
> 
> jrose
> 
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.digium.com/pipermail/asterisk-dev/attachments/20120203/d88a2294/attachment.htm>