[asterisk-bugs] [JIRA] (ASTERISK-28470) Mutex deadlock in audio_audiohook_write_list

[Kevin Harwell (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-28470?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=247527#comment-247527 ] 

Kevin Harwell commented on ASTERISK-28470:
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There shouldn't be a problem here. From what I can tell the lock is reentrant. Meaning the same thread can acquire the lock multiple times.

How have you become aware you have a deadlock? Please provide a backtrace from the system when the problem manifests. You can use the ast_coredumper script to get a running backtrace (note however getting a running backtrace can interrupt calls). More info here:

https://wiki.asterisk.org/wiki/display/AST/Getting+a+Backtrace

> Mutex deadlock in audio_audiohook_write_list
> --------------------------------------------
>
>                 Key: ASTERISK-28470
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-28470
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: General
>    Affects Versions: 16.3.0
>         Environment: CentOS 6.10
>            Reporter: Andre Heber
>
> In main/audiohook.c in the function "audio_audiohook_write_list" is the following code:
> {code:java}
>     ast_audiohook_lock(audiohook);
> 		if (audiohook->status != AST_AUDIOHOOK_STATUS_RUNNING) {
> 			AST_LIST_REMOVE_CURRENT(list);
> 			removed = 1;
> 			ast_audiohook_update_status(audiohook, AST_AUDIOHOOK_STATUS_DONE);
> 			ast_audiohook_unlock(audiohook);
> {code}
> But "ast_audiohook_update_status" also locks "audiohook" "if (audiohook->status != AST_AUDIOHOOK_STATUS_RUNNING)", which results in a frozen thread.
> This happens 3x in "audio_audiohook_write_list" and 1x in "dtmf_audiohook_write_list".



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