17.10: gnome-shell regularly locks up in VirtualBox - unity is still fine

[Alexander Jones]

Repro:

 * VirtualBox Version 5.2.8 r121009 (Qt5.6.2)
 * Windows 7 host
 * VirtualBox 3D Acceleration enabled, given 128MB video memory
 * VirtualBox guest additions installed.
 * Log in with either Ubuntu (Xorg) or GNOME (Xorg) (both are actually gnome-shell)
 * Open a File browser or a Terminal, or probably anything
 * Maximize the window (this part is also pretty slow)
 * Unmaximize the window

Expected:

 * Maximize and unmaximize take a fraction of a second. System operates as normal afterwards.

Actual

 * Maximize is already pretty slow - the first frame of the animation takes a few seconds to render and then freezes, then a few more seconds later the window is full screen.
 * Unmaximize just locks up gnome-shell for 30s or so. Eventually it repaints, but the shell is now completely unusable - no more repaints. I waited minutes and it still didn't come back to life. This happens 100% of the time.

I *can* switch to another VT, and log in in text mode, and see that gnome-shell is occasionally showing activity at 40+%. I can switch back to GNOME and still see the frozen screen.

NB: Unity works fine, as it did in 17.04.

I suspect something that gnome-shell does with OpenGL that unity didn't do is triggering a software fallback or something. Is there any way to run a diagnostic to test / benchmark the OpenGL capabilities used by gnome-shell?

Thanks, apologies in advance if I missed any critical information. Happy to provide more system details.

[Daniel van Vugt (vanvugt)]

A lock up is probably the result of some component crashing. So to debug this problem we will probably need to get some crash reports. Please do these (in the VM):

1. Apply the workaround from bug 994921.

2. Reproduce the problem, then look in /var/crash for crash files, and run:
   ubuntu-bug /var/crash/YOURFILE.crash

3. If everything goes well, 'ubuntu-bug' will create a new bug report each time you run it. So let us know here those new bug IDs.

Please don't try attaching crash files to existing bugs because we can't debug them that way. They must be uploaded using the 'ubuntu-bug' command.

[Launchpad Janitor (janitor)]

[Expired for gnome-shell (Ubuntu) because there has been no activity for 60 days.]