Re: Linux kernel: powerpc: KVM guest can trigger host crash on Power8

Hi Michael!

On 11/1/21 07:53, Michael Ellerman wrote:

Sure, will give that a try.

I was able to crash my machine over the weekend, building openjdk, but I
haven't been able to reproduce it for ~24 hours now (I didn't change
anything).

I made another experiment and upgraded the host to 5.15-rc7 which contains your
fixes and made the guests build gcc-10. Interestingly, this time, the gcc-10
build crashed the guest but didn't manage to crash the host. I will update the
guest to 5.15-rc7 now as well and see how that goes.

Can you try running your guests with no SMT threads?

I think one of your guests was using:

  -smp 32,sockets=1,dies=1,cores=8,threads=4

Can you change that to:

  -smp 8,sockets=1,dies=1,cores=8,threads=1


And something similar for the other guest(s).

Sure. I will try that later. But first I want to switch the guests to 5.15-rc7 as well.

If the system is stable with those settings that would be useful
information, and would also mean you could use the system without it
crashing semi regularly.

Gotcha.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@debian.org
`. `'   Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
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