Thread Growth and App Hang in Audio Conferences

[Mahe2027]

Hi linphone team,

Describe the bug

When creating audio conferences, the number of threads labeled as "video conference" grows continuously, even though the conferences are strictly audio-based. In a single conference, the total thread count increased from 69 to 72. If multiple audio conferences are created without exiting or killing the app, the app eventually hangs and crashes.

This issue was tested and reproduced using the latest Linphone official app from the Play Store, as well as with custom apps built using the Linphone SDK. The SDK versions 5.2.107 and later all exhibit the same issue.

Screenshots are attached showing the total threads increasing from 69 to 72 after creating a single conference.
To Reproduce

Create an audio conference using the Linphone SDK or the official Linphone app.
Use the command adb shell top -H -p [App Process ID] to monitor thread growth.
Observe threads labeled as "video conference" growing after creating the conference.
Repeat the process to create multiple conferences without killing the app and note app instability.

Expected behavior

Thread counts should not grow unexpectedly during audio conferences. The app should remain stable, even after creating multiple conferences.
Please complete the following information

Device: multiple android devices
OS: Android 11 (tested on other versions as well)
Version of the App: Latest Linphone official app from the Play Store
Version of the SDK: 5.2.107 and later
Source: Maven repository

Please include logs to help trace the issue.

Screenshots

Additional context

It is unclear why threads are labeled as "video conference" in this purely audio scenario. Could this be related to improper thread management within the SDK or the official app?

Thanks
Mahee

[Mahe2027]

Hi,

I have also tested this issue with the latest Linphone official app, and the behavior remains the same.

Attached are screenshots showing the thread count increasing.

Just to clarify, I'm creating the conference on the device (not on the server).

[Viish]

Hi @Mahe2027,

5.2 SDK is not supported anymore, please reproduce with latest 5.3 or current 5.4-alpha one.

Cheers,

[Viish]

If you do reproduce, please attach logs.

[Mahe2027]

Hi @Viish ,

Thanks for replay.

FYI - These screenshots are from SDK version 5.3.95 and the latest Linphone-Android app from the Play Store. The issue persists with both, even with the latest versions available.

[Viish]

Please attach logs then.

[Mahe2027]

Hi @Viish

I am adding logs for creating two conferences—first and second—after launching the Linphone official app.

When I initiated the first conference, it created three conference-related threads:
    Audio conferenc thread
    Two additional threads labeled as Video conferenc

After terminating the first conference, the threads did not get cleared; they remained in a sleeping state.

When I initiated the second conference, three new threads were created, making a total of six conference-related threads (three from the first conference and three new ones).

This pattern continues with every new conference initiated. The threads keep growing, and once the device thread limit is reached, the app starts hanging and eventually results in an ANR (Application Not Responding).

I am attaching the following files:
linphone-thread-growth-issue-logs-first-conference.txt

linphone-thread-growth-issue-logs-second-conference.txt
linphone-thread-growth-issue-logs-second-conference.txt

linphone-thread-growth-issue-logs-first-conference.txt

Additionally, I am attaching a screenshot showing the thread count:

0 threads for conferences when the app is launched

3 threads after the first conference

6 threads after the second conference

[smorlat]

Hi,

Thanks for your report. This issue is fixed in master branch. Release 5.4 scheduled for mid-january wil also contain the fix.

Best regards,

Simon

[Mahe2027]

Hi,

Thank you for your response. Could you please let me know which specific commit has resolved this issue? It would help me verify and test the fix on my end before the next release.

Thanks
Mahee