Segmentation faults when using shapes with automated user Debug Tools

[louwrentius]

Describe the Bug

This issue originates from this forum thread

During our investigation on our Staging/Acceptance environment for another stability issue, we found out we can reproducibly crash coolwsd with a segmentation fault, when we run the automated typer with two simultaneous users in the same document.

Per instruction on the forum thread, I've tried to collect information with gdb (see attachments). Please note that I'm inexperienced with gdb and may require additional guidance to collect the information you need to troubleshoot this issue.

Steps to Reproduce

1. Go to Nextcloud Files
2. Open a (new or existing) document for testing
3. Start the Debug Tools (CTRL-Shift-ALT-D)
4. Under Functionality: check 'Typer'
5. Under Automated User, check both 'Enable automated user' and 'Insert and delete shape'
6. The Debug Tools will start to type content and insert/delete random shapes.
7. Now, use a second user account to open the same document and follow steps three to five. In our case, this triggers a segmentation fault and (usually) an automated restart of the coolwsd service.

Expected Behavior

No crash / segmentation faults.

Actual Behavior

As the second user enables the automated user and the 'insert and delete shape' option in the debug tools, it takes mere seconds to 'crash' coolwsd / cooforkit.

Attachments

make-run-output.txt.zip coolwsd-SIGSEGV-snippet.txt coolwsd-gdb-trace.txt

Desktop

• Collabora version: compiled from source (main branch) on June 24th
• OS and version: Debian 12
• Browser and version: any browser

This issue is also confirmed on ubuntu 22.04 with .deb from collabora mirror: 24.04.4-1