On Fri, Jul 30, 2021 at 2:00 PM Roger Heflin <rogerheflin(a)gmail.com> wrote:
If it was just a plasma crash, then ssh and/or the alt keys would have
worked to switch terminals.
Details said neither worked. The kernel and/or a significant part of
userspace was deadlocked and/or crashed.
I wonder if logs contain anything... i.e. from the boot following the
failed update, use journalctl -b-1 and if it's 5 boots back use -b-5
It might have the start of the problem anyway. I also suspect a
deadlock. It can make it seem like ssh is dead but it's just super
slow. Or may even time out unless a session has already started.
Workstation edition and KDE spin have improved resource control, which
is a work in-progress (also on KDE you will need to install
uresourced). This attempts to ensure minimum resources are available
for the desktop to be responsive. One possible limitation is IO
pressure, we're not quite there yet implementing IO isolation. A
deadlock though is a different problem so the resource control work
wouldn't help.
If you ever see "task xxx:yyy blocked for more than 120 seconds" it's
best to issue sysrq+w (i.e. echo w > /proc/sysrq-trigger) to dump
extra debugging information into the kernel message buffer, and then
file a bug attaching dmesg.
--
Chris Murphy