[asterisk-dev] Asterisk 1.4.15 ast_service_stop() function deadlock?

[Dmitry Andrianov]

I guess you meant ast_autoservice_stop not ast_service_stop.
Honestly I have no idea what causes your problem - it is something for Russell to look at probably.
However, I'm almost sure that upgrading tor latest SVN 1.4 branch will fix the problem because of commit 90967.

From: asterisk-dev-bounces at lists.digium.com [mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Paulo Garcia
Sent: Tuesday, December 11, 2007 10:44 PM
To: Asterisk Developers Mailing List
Subject: [asterisk-dev] Asterisk 1.4.15 ast_service_stop() function deadlock?

Hi,

well, it isn't really a deadlock, but I think it is something wrong....

in my channel driver, I have a fax detection procedure that calls ast_exists_extensions() to check if there is a 'fax' exten available to jump for.

My test environment is an Asterisk box with FXO interface and another non-asterisk box with FXS interface. The FXS side originates the call and the asterisk box answer the call.

I always used the following dialplan for testing:

exten => s,1,Answer(1000);
exten => s,n,Record(test:ulaw|0|0)
exten => s,n,NoOp(${REMOTESTATIONID})

When the Asterisk side answer the call, the FXS side starts a Fax transmit. Of course the fax won't be received since there is no Rx application running on Asterisk side.

The problem is that, when the Asterisk detects the fax signal and calls ast_exists_extensions(), the function ast_service_stop() only returns when the call finishes. I followed the stack and it seems that the ast_service_stop function stay the following point:

00234    /* Wait for it to un-block */

00235    while (ast_test_flag<http://www.asterisk.org/doxygen/1.4/utils_8h.html#0cba63300a5690b7f297b26179882cd9>(<http://www.asterisk.org/doxygen/1.4/structasent.html#24fea160601399d6d7a15f28b22bebd7>

chan<http://www.asterisk.org/doxygen/1.4/structasent.html#24fea160601399d6d7a15f28b22bebd7>, AST_FLAG_BLOCKING<http://www.asterisk.org/doxygen/1.4/channel_8h.html#d032a9ab2ed31c90af611a3c6221925306284ba3d5b82164197739aff2f52568>))

00236       usleep(1000);

So, If my call takes 3 minutes, the Asterisk will stay on that point for 3 minutes and return only to hangup.

Also, I tested using Asterisk 1.4.14 and this problem doesn't happen. I saw that 1.4.15 has a lot of changes on that function, to keep dtmf frames but I couldn't figure out why these changes starts to cause the problem in 1.4.15 since that loop exists on both versions.

Any idea?

Note: I used the Record() application because it has the same loop to wait finish that my fax rx application has. I swapped them to be sure that it is not only a problem in my application.

--
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Paulo Garcia
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