[Xen-devel] Xen stable-4.11 crash when trying to start a VM on fedora 29

[Mathieu Tarral]

Hi,

I managed to compile and install Xen from source,using the  stable-4.11 branch.

I configured my VMs in libvirt, but when I try to start one of them, the host completely crashes after a few seconds (the VM is never started), and reboots.

I ran dmesg -w before starting the VM, and the ouput
is 2 general protection faults:
https://gist.github.com/Wenzel/763b17fae773f7dd6b1d8b303187f3c0


Can anyone look into this and tell me if this is a bug in Xen ?

Thanks !
--
Mathieu Tarral

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[Jan Beulich]

I managed to compile and install Xen from source,using the stable-4.11
branch.
I configured my VMs in libvirt, but when I try to start one of them, the
host completely crashes after a few seconds (the VM is never started), and
reboots.
I ran dmesg -w before starting the VM, and the ouput
https://gist.github.com/Wenzel/763b17fae773f7dd6b1d8b303187f3c0

Without a full hypervisor log this is going to remain guesswork, but
could you check whether "pcid=no" and/or "pv-l1tf=no" on the Xen
boot command line help?

Jan

[Mathieu Tarral]

Hi Jan,

Post by Jan Beulich
Without a full hypervisor log this is going to remain guesswork, but
could you check whether "pcid=no" and/or "pv-l1tf=no" on the Xen
boot command line help?

placeholder root=UUID=f4dcb7e6-e430-4b8b-8e83-5deb3522c88b ro no_timer_check
console=tty1 console=ttyS0,115200n8 net.ifnames=0 biosdevname=0
I hope that helps.

I'm afraid I'm entirely lost as to what you're trying to tell me, the
more in a private mail. I've asked you to try out extra hypervisor
command line options, and you reply with what some random
kernel command line of yours looks like.

I apologize, I read your reply too fast last time /o\

So I try adding "pcid=no", "pv-lt1f=no" and then "pcid=no pv-lt1f=no" in
/etc/sysconfig/grub GRUB_CMDLINE_XEN, Xen it still crashing, nothing in dmesg.

Are you interested in investigating this bug ?
To me anything that crashes Xen is worth looking at.

Best regards,
Mathieu

[Jan Beulich]

Post by Mathieu Tarral

Post by Jan Beulich
Without a full hypervisor log this is going to remain guesswork, but
could you check whether "pcid=no" and/or "pv-l1tf=no" on the Xen
boot command line help?

placeholder root=UUID=f4dcb7e6-e430-4b8b-8e83-5deb3522c88b ro no_timer_check
console=tty1 console=ttyS0,115200n8 net.ifnames=0 biosdevname=0
I hope that helps.

I'm afraid I'm entirely lost as to what you're trying to tell me, the
more in a private mail. I've asked you to try out extra hypervisor
command line options, and you reply with what some random
kernel command line of yours looks like.

I apologize, I read your reply too fast last time /o\
So I try adding "pcid=no", "pv-lt1f=no" and then "pcid=no pv-lt1f=no" in
/etc/sysconfig/grub GRUB_CMDLINE_XEN, Xen it still crashing, nothing in dmesg.

Without a log I can't tell whether the options were actually in effect.

Post by Mathieu Tarral
Are you interested in investigating this bug ?

If "you" stands for the community, then yes. Personally I can't
promise I have the cycles to do so, especially as long as there's
neither a simple and clear repro nor at the very least a hypervisor
log covering the crash.

Post by Mathieu Tarral
To me anything that crashes Xen is worth looking at.

Of course, but we need some data to work from.

Jan