Time to time my mouse cursor stalls, and it can be freed only by reloading the psmouse daemon:
$ sudo rmmod psmouse
$ sudo modprobe psmouse
This happens, when I'm using my laptop's trackpad, and this problem goes away if I plug in USB mouse. I haven't used USB mouse for longer time to experience the same stalling symptoms, though.
When it stalls, the cursor remains visible, but it doesn't move. Strangely, the trackpad switches to scroll mode, ie, if the cursor hovers above scrollable content, trying to move the cursor up/down results in the content scrolling. Perhaps it should be added that normally this would happen, if I do the two finger up/down swiping gesture (this is multi-touch trackpad).
I could speculate that this happens under high processor/memory load conditions, but then again, my computer is under such conditions very often, so this is not necessarily the cause. Another possible influencer is the VirtualBox, as I keep running a virtual machine in background basically all the time. Perhaps VirtualBox is the one tampering with psmouse daemon.
I've survived with psmouse daemon reloading for quite a time, but enough is enough, I'd like this stupid problem to go away for ever.