YouTube is completely unusable with CanvasBlocker

[Mensh123]

When i watch YouTube with this extension enabled, the site can randomly be extremely slow. Also, once I reach the end of the buffer the page initially loads with, the spinner stays for a bit before being replaced with a YouTube error message. This issue occurs even when no further add-ons are enabled.

Short summary of relevant bits:

• OS: Fedora Linux 43
• Firefox version: 148.0b3 (Dev edition)

troubleshooting information

[Mensh123]

Also, you'd think turning off CanvasBlocker via its own menu would fix the issue, but it doesn't CanavasBlocker needs to be fully disabled in the Firefox Add-ons page.

[yellowtvgit]

I'm experiencing something similar. Windows 10, Firefox 148.0b3. I would say the issue appeared around the Firefox major version bump to 148.

Upon initial load of the Youtube home page, the browser's RAM usage balloons to over 3x normal with most elements failing to load. A small popup usually appears "This page is slowing down Firefox. To speed up your browser, stop this page." Then the stalled elements may load eventually and the popup disappears with RAM usage remaining bloated. This is with CanvasBlocker as the only active extension. I've experienced similar hangs on the basic google.com search page after searching for something, but those issues have been less consistent. I haven't yet noticed these issues on other sites.

[raphaelyancey]

Also experiencing this on Ubuntu & Firefox 148.0b3 with extreme RAM usage.

[Ra2-IFV]

Bugzilla: https://bugzilla.mozilla.org/show_bug.cgi?id=2011064

[firepainting]

Also experiencing this but only with embedded YouTube videos on Firefox Developer 148.0b4. No issues on youtube.com itself, though.

On Linux Mint 21.3 but no issues at all on the regular Firefox it ships with (147.0).

[matthiasfostel]

Issue seems to happen even on older versions of CanvasBlocker and Firefox 148, so seems to be a Firefox issue.

[Rob--W]

I haven't looked at the profile or any code, but given the above remark about this being potentially new in Firefox 148, the following bit might be of interest for investigation.

One significant change in Firefox 148 is that content scripts are now run in more about:blank documents. Previously, when an iframe was created and appended to the document, the content script would not immediately run because the initial about:blank is initialized asynchronously.

Starting from Firefox 148, the initial about:blank is initialized synchronously, and any content scripts registered for all frames and including match_about_blank (or match_origin_as_fallback) will run immediately.

I recently witnessed another extension behaving buggy when it encountered earlier script execution, for details see: https://bugzilla.mozilla.org/show_bug.cgi?id=2004404#c12