GUI hangs when system is up for (multiple of) 50 days
When uptime crosses a multiple of 2^32 milliseconds (~49.7 days), windows stop responding to keyboard and mouse events. Restarting X clears the problem (until the uptime passes another ~49.7 days). This was originally observed with gnome-session, but it is also observable in mutter, and the latter was easier to test.
Here is my basic testing process. As it is difficult to manipulate the system's monotonic clock, I used a hacked version of the Xorg server that would use "wall" time for its clock instead of the system's monotonic clock. With this "wall" clock, an overflow/wrap-around event occurs around Jan 16 2018 17:24:15 UTC.
- Set the date to a few minutes before the overflow time
- Start up [hacked] Xorg
- Start up mutter
- Start up a couple of regular X clients (e.g. xterm, xlogo)
- Hit
Alt
-Tab
several times to switch between windows - Wait fot the clock overflow event to pass
- Hit
Alt
-Tab
several times to switch between windows
-
Expected result: focus switches with each
Alt
-Tab
- Actual result: focus switches only the first time, after which key presses and button presses have no effect