On 11/02/2016 08:23 PM, Sebastian Andrzej Siewior wrote: > On 2016-11-01 13:15:53 [+0300], M. Vefa Bicakci wrote: >> Hello Sebastian, > > Hi, > >> The patch fixes the kernel oops for me. >> >> I am using a custom 4.8.5-based kernel on Qubes OS R3.2, which is based >> on Xen 4.6.3. Apparently, Xen also has a similar bug/flaw/quirk regarding >> the allocation of package identifiers for the virtual CPUs. >> >> Prior to your patch, my Xen-based virtual machines would intermittently >> crash most of the time at boot-up with the backtrace reported by Charles. >> Due to this, I was under the impression that this is a subtle race >> condition. > > how hard is it to get such a xen setup up and running?
Hello Sebastian, Sorry about my late reply! The set-up I use is a bit involved/complicated. To replicate it, you would need to install Qubes OS R3.2 (assuming that you have compatible hardware with a lot of RAM) and then build a custom 4.8.y-based kernel with a set of cherry-picked commits. After installing this kernel in dom0 with dnf or rpm, you would need to run: # Generate a domU initrd and copy the kernel image and the generated # initrd to Qubes OS's domU kernel directory (/var/lib/qubes/...) $ sudo /usr/sbin/qubes-prepare-vm-kernel <kernel_version> # From now on, use kernel_version when starting domU instances. $ qubes-prefs -s default-kernel <kernel_version> Afterwards, starting a domU (i.e., AppVM in Qubes OS terminology) should exhibit the issue in question related to RAPL: $ sudo truncate -s0 /var/log/xen/console/guest-<app_vm_name>.log $ qvm-start --debug <app_vm_name> $ cat /var/log/xen/console/guest-<app_vm_name>.log As you may appreciate, the set-up is a bit involved. Nevertheless, in case you would like to replicate my set-up, I can try to publish my linux-4.8.y-based git branch so that you can build a similar kernel as the one I use. Vefa
