Mir locking up when switching VTs after stopping lightdm

[Michał Sawicz]

Steps:
* stop lightdm
* follow https://wiki.ubuntu.com/Process/Merges/TestPlans/Mir#Test_Plan

Expected:
* Switching to Mir VT works

Current:
* When trying to switch to the Mir VT, Mir locks up trying to render, never completing, and not handling Ctrl+Alt+F* presses

[Michał Sawicz (saviq)]

When attaching gdb to the demo server, http://paste.ubuntu.com/24801119/ is the backtrace.

[Daniel van Vugt (vanvugt)]

Sounds serious, till proven otherwise...

[Daniel van Vugt (vanvugt)]

I can't reproduce the bug using either the latest release or building fresh from lp:mir.

Also, your attached stack trace seems to be incomplete(?) - there are apparently no compositor threads, so nothing to redraw the screen :)

Can you collect the server log from when the problem occurs?

[Alan Griffiths (alan-griffiths)]

The essential step here is stopping lightdm. After which it seems Mir fails to restart compositing when the VT switches back. This scenario is low priority.