Gnome Shell starts freezing every few seconds
Affected version
Fedora 33, Gnome Shell 3.38.1, Wayland
Bug summary
Gnome Shell freezes for about 200ms every 10-20 seconds. Mouse cursor and animations stop, key strokes get delayed resulting in duplicate letters, mismatched Shift/Ctrl/etc. modifiers, and so on.
Somehow this happens consistently after I use the text annotation tool Doccano. So far, it's been 3-4 times, and I've never seen Gnome Shell do this before.
Steps to reproduce
(Sorry, these steps would be quite painful to perform - but hopefully my description gives some clues.)
- Run Doccano (in a Docker container)
- Open the website in Firefox
- Upload some text, create labels
- Start annotating text:
- Select a word or a phrase
- Type a keyboard shortcut to add a label
- Repeat a few hundred times
What happened
Gnome Shell starts freezing.
It also starts using up more and more RAM - went up to 5GB once - but freezing starts happening way before RAM becomes a problem.
Killing Docker, Firefox, etc. makes no difference. There is nothing using up CPU, memory, disk, etc.
What did you expect to happen
Gnome Shell should be working as usual.
Relevant logs, screenshots, screencasts etc.
The only action that I don't normally perform would be selecting pieces of text over and over again; I can't think of what else makes Doccano trigger this bug.
I tried running strace
to see what gnome-shell is doing while freezing. I got two almost identical logs, and I see lots of mprotect
calls at the time when I think it was freezing: