After login on a x11 gnome gdm3 sesssion, display hangs, crash, becomes black, and occasionally freeze the computer. Which is an imac 27" 2011. But - i'm not sure it's a mesa bug, maybe a linux kernel bug triggered by the mesa update - i think it's appearing only on large displays like 2560x1440. - i don't know how to get logs from previous boots with journalctl
I remember something about "cs ring radeon", etc.. Please help because it's a real bug ! Jérémy