I also experience this problem since I updated yesterday. I am using Kubuntu 16.04 with KDE backports enabled. I also have a Ryzen 1800X and an Asrock X370 Gaming professional
I experience this either when I boot and don't log in promptly or when I enter the lockscreen. After reading this page I tried to run seq 1 | xargs -P0 -n1 md5sum /dev/zero & as root to always keep one CPU core busy and indeed this seems to prevent the lockscreen problem... I would also like to note that the system was not 100% frozen, once every few minutes it seemed to response for a short time, enabling me to switch to the TTY. Then I always saw some processes hanging at 100% that I could not kill, or the kill was delayed for a long time. I always see the errors in the initial posts during that time. The TTY seemes to work fine though, once entered though. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1690085 Title: Ryzen 1800X freeze - rcu_sched detected stalls on CPUs/tasks To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1690085/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
