Summary:	ASTERISK-30155: core: CLI using -rx of "core show channels" returns empty
Reporter:	Spilios Georgakopoulos (sgeorgak)	Labels:	fax
Date Opened:	2022-07-25 04:39:29	Date Closed:
Priority:	Minor	Regression?
Status:	Open/New	Components:	Core/General
Versions:	18.6.0	Frequency of Occurrence	Occasional
Related Issues:
Environment:	RedHat Linux	Attachments:	( 0) core_dump_txt.zip ( 1) core_dumps.png ( 2) core_show_channels_result.png ( 3) new_core_dumps_txts.zip
Description:	Hello, We have built a Voicemail platform for Telecom services in a Telecom Client based on Asterisk (18.6) and Opensips (3.1.0). Sometimes, when we execute the command "asterisk -rx 'core show channels'", it returns nothing. The service is up and running without facing any issue. This issue was reproduced on the test environment, but no logs were produced. Have you ever faced the same problem? We need your support since it is a production issue and affects the service. Br, Spilios G.
Comments:	By: Asterisk Team (asteriskteam) 2022-07-25 04:39:34.513-0500 Thanks for creating a report! The issue has entered the triage process. That means the issue will wait in this status until a Bug Marshal has an opportunity to review the issue. Once the issue has been reviewed you will receive comments regarding the next steps towards resolution. Please note that log messages and other files should not be sent to the Sangoma Asterisk Team unless explicitly asked for. All files should be placed on this issue in a sanitized fashion as needed. A good first step is for you to review the [Asterisk Issue Guidelines|https://wiki.asterisk.org/wiki/display/AST/Asterisk+Issue+Guidelines] if you haven't already. The guidelines detail what is expected from an Asterisk issue report. Then, if you are submitting a patch, please review the [Patch Contribution Process|https://wiki.asterisk.org/wiki/display/AST/Patch+Contribution+Process]. Please note that once your issue enters an open state it has been accepted. As Asterisk is an open source project there is no guarantee or timeframe on when your issue will be looked into. If you need expedient resolution you will need to find and pay a suitable developer. Asking for an update on your issue will not yield any progress on it and will not result in a response. All updates are posted to the issue when they occur. Please note that by submitting data, code, or documentation to Sangoma through JIRA, you accept the Terms of Use present at [https://www.asterisk.org/terms-of-use/|https://www.asterisk.org/terms-of-use/]. By: Joshua C. Colp (jcolp) 2022-07-25 05:30:29.248-0500 We suspect that you have a deadlock occurring within Asterisk. Please follow the instructions on the wiki [1] for obtaining debug relevant to a deadlock. Once you have that information, attach it to the issue. Be sure the instructions are followed exactly as the debug may otherwise not be useful. Thanks! [1] https://wiki.asterisk.org/wiki/display/AST/Getting+a+Backtrace#GettingaBacktrace-GettingInformationForADeadlock By: Joshua C. Colp (jcolp) 2022-07-25 05:31:17.656-0500 Please also note that 18.6.0 is an old version. Test using the latest version of 18 (18.13.0) to ensure the issue is not already fixed. This is also a community issue tracker, if there does appear to be an issue there is no time frame on when such a thing would get fixed. By: Spilios Georgakopoulos (sgeorgak) 2022-07-27 04:14:39.484-0500 Hello, Attached you may find the core dumps files. Please, let us know about your analysis as soon as possible, because it affects the production environment. Thank you. By: Joshua C. Colp (jcolp) 2022-07-27 04:27:32.553-0500 Asterisk does not appear to be blocked in this backtrace. It appears to be completely idle. The backtrace has to be taken when it is blocked and showing the issue you have described. You also did not state whether you upgraded Asterisk or not to a current version of 18. Finally I must state again that there is no time frame on when or even if this issue will get looked at if accepted, despite it causing you issues in production. By: Spilios Georgakopoulos (sgeorgak) 2022-07-28 05:43:03.653-0500 Hello, Attached you may find 6 core dumps during the unavailability of asterisk to execute the command. We have not tried to reproduce the case in the version 18.13 yet. Thank you in advance. By: Joshua C. Colp (jcolp) 2022-07-28 05:45:42.628-0500 I don't see any deadlock or issue in these backtraces, or even an attempt to execute a CLI command. The only thing I see is a fax in progress. I think before going any further we will definitely need reproduction under latest version. By: Spilios Georgakopoulos (sgeorgak) 2022-07-28 06:12:51.982-0500 Hello, Attached you may view the lines and the files that the CLI command is executed. Do you observe any issue regarding the CLI command? Thank you. By: Joshua C. Colp (jcolp) 2022-07-28 06:18:21.424-0500 That's a temporary buffer with old information in it. It's not actually executing a CLI command at the time. Have you actually meant that the command does complete, but doesn't show anything? If so what does it actually show? The header for channel listing? Nothing at all? And still, trying on the latest would be necessary as I'm not aware of anything off the top of my head in that area and don't want to go searching through history and logs for things. By: Spilios Georgakopoulos (sgeorgak) 2022-07-28 06:32:12.301-0500 When we execute the CLI command, we will see as output the result of the image attached. When we experience the issue, the command returns an empty reply. By: Spilios Georgakopoulos (sgeorgak) 2022-08-01 02:58:12.908-0500 Hello, Have you found any possible solution regarding the issue? Thank you. By: Joshua C. Colp (jcolp) 2022-08-01 03:46:10.054-0500 If there are any comments or further questions then they'll be posted on this issue. As I've stated before though, there is no time frame on when this would be looked into. If you're expecting it to be resolved quickly it is unlikely that will happen. By: Michael Bradeen (mbradeen) 2022-08-01 10:35:10.848-0500 Hello [~sgeorgak] - please help us be clear on the nature of this issue, does the CLI freeze when the "core show channels" option is used (meaning asterisk blocks and does not return anything) or is the issue that the cli returns 0 calls when there are calls running?  And also to be clear, Asterisk continues to process calls without issue during this time, correct? By: Spilios Georgakopoulos (sgeorgak) 2022-08-01 10:48:55.247-0500 Hello, Yes, the CLI freezes and no output is return. It is not the case that the CLI returns 0 when the calls are running. It's just that the CLI does not return the active channels when prompted. From the core dumps, you may find the time that the command was executed. Thank you. By: Joshua C. Colp (jcolp) 2022-08-02 04:00:19.843-0500 So when you execute "core show channels" it just hangs there, indefinitely? Do other commands behave the same way? By: Spilios Georgakopoulos (sgeorgak) 2022-08-02 04:18:22.091-0500 Hello, When we execute the "core show channels", the CLI returns nothing as an output and it does not hang indefinitely. The command is executed and it returns an empty output. We have observed that sometimes needs up to 60 times to execute the command so that it can be executed correctly. Also, this is an issue that we face when Asterisk does not serve many calls at the time that the command is executed. By: Joshua C. Colp (jcolp) 2022-08-02 04:24:14.088-0500 Okay, so the CLI doesn't freeze then. It just doesn't output anything as I originally understood. By: Spilios Georgakopoulos (sgeorgak) 2022-08-02 04:57:06.953-0500 Yes, this is the issue. Do you have any idea about the cause or any possible solution? By: Joshua C. Colp (jcolp) 2022-08-02 05:11:11.587-0500 Any further comments will be posted here. I don't have any. By: Spilios Georgakopoulos (sgeorgak) 2022-09-05 05:44:56.750-0500 Hello, Do you have any news regarding this issue? Thank you By: Joshua C. Colp (jcolp) 2022-09-05 06:50:33.796-0500 Any news or updates will be posted on the issue.