host crash - guest_4.o#sh_page_fault__guest

r1

Ok.. so its not related then.

Do you have other leads - such as crash logs or kern.log to guess?

Steve_Sibilia

Yes,
here: https://cloud.sinapto.net/index.php/s/13nUsnunRKmdUBC
you can find crash log. For what I can understand it is related to an host which was pv with an older version of the tools (7.2). After last crash I've update tools to the latest version hoping that this will fix the issue.
All the crashes (4 so far, on 2 different xcp hosts) happened outside peak hours for our infrastructure (friday evening after business hours and saturday during lunch) so I don't think is load average related but I'm not certain about it.
Let me know if you need further informations.
Thanks
Steve

r1

Guest tools should not be able to crash host - it will be treated as critical bug. Your stack is similar to that of reported earlier. And even though you have updated Xen version, the trigger could be something else...

Danp

FWIW, it appears that my fully patched 7.6 xcp host also rebooted the morning of 2/27

System Booted: 2019-02-27 04:46

I haven't dug into the logs yet.

r1

@Steve_Sibilia @Danp @borzel can you share # xenpm get-cpuidle-states and BIOS power saving settings?

Danp

Here the cpuidlestates.txt. Unsure how to get the BIOS settings without rebooting.

Steve_Sibilia

@r1 yes for sure.
Here: https://cloud.sinapto.net/index.php/s/0X8GdLxnTrw6bmd the output pf get-cpu-idle-states.
Power management is set up for maximun performance, power cap is disabled.
The system is a Dell poweredge r640.
Let me know if you need more details.
Steve

r1

@stormi

While digging on multiple things I'm curious on one patch

https://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=9dc1e0cd81ee469d638d1962a92d9b4bd2972bfa

It seems to have been applied on

But its not there on

stable-4.8 https://xenbits.xen.org/gitweb/?p=xen.git;a=history;f=xen/arch/x86/mm/shadow/multi.c;h=7dc39d75651e0bd85fe9a4b5c6c586648d7a7ab2;hb=refs/heads/stable-4.8

and

stable-4.7 https://xenbits.xen.org/gitweb/?p=xen.git;a=history;f=xen/arch/x86/mm/shadow/multi.c;h=7dc39d75651e0bd85fe9a4b5c6c586648d7a7ab2;hb=refs/heads/stable-4.7

And I think this could have relation of the host crash mentioned above. The function guest_walk_to_gfn is used in stable-4.7 but not at places mentioned by this specific patch.

Will try to find more on this, my tomorrow.

Steve_Sibilia

A quick update.
This morning we had another crash. Same host, same guest involved.

stormi

You can try this workaround: boot your host with the "pcid=0" parameter. This will likely have an impact on performance but should avoid the crash.

Reference: https://lists.xenproject.org/archives/html/xen-devel/2019-01/msg00006.html

stormi

Security advisories have just been published on http://xenbits.xen.org/xsa/

The host crash you experienced is probably related to http://xenbits.xen.org/xsa/advisory-294.html

We will provide updated Xen packages as soon as they are ready.

Steve_Sibilia

Thank You for the update.