Bug 508580 – app-emulation/xen-4.4.0 with kernel 3.14.1 in dom0 - fails to load modules / panic

• Status: RESOLVED OBSOLETE
• Product: Gentoo Linux

[Description Another Mortal 2014-04-24 09:17:24 UTC]

Created attachment 375582 [details]
syslog excerpt

Hmm… it looks like we have a _killer_ combination here.

* xen-4.4.0 + hardened-sources-3.14.1
  panic on one box
  unable to load modules on another

* xen-4.4.0 + gentoo-sources-3.14.1
  panic on the box that could not load modules
  I haven’t bothered trying on the other one

Unfortunately, I could not capture output for the panics,
but I’m attaching a syslog excerpt for the modprobe issue.


Interestingly, xen-4.4.0 + hardened-sources-3.13.9 works fine on both.
Also, both gentoo and hardened 3.14.1 kernels by themselves work fine.

Here are the kernel settings relevant to Xen:
-----
CONFIG_XEN=y
CONFIG_XEN_DOM0=y
CONFIG_XEN_PRIVILEGED_GUEST=y
CONFIG_XEN_PVHVM=y
CONFIG_XEN_MAX_DOMAIN_MEMORY=500
CONFIG_XEN_SAVE_RESTORE=y
# CONFIG_XEN_PVH is not set
CONFIG_PCI_XEN=y
CONFIG_XEN_PCIDEV_FRONTEND=m
CONFIG_XEN_BLKDEV_FRONTEND=m
CONFIG_XEN_BLKDEV_BACKEND=y
CONFIG_XEN_NETDEV_FRONTEND=m
CONFIG_XEN_NETDEV_BACKEND=y
CONFIG_INPUT_XEN_KBDDEV_FRONTEND=m
CONFIG_HVC_XEN=y
CONFIG_HVC_XEN_FRONTEND=y
CONFIG_TCG_XEN=m
CONFIG_XEN_WDT=m
CONFIG_XEN_FBDEV_FRONTEND=m
# CONFIG_XEN_BALLOON is not set
CONFIG_XEN_DEV_EVTCHN=y
CONFIG_XEN_BACKEND=y
CONFIG_XENFS=y
CONFIG_XEN_COMPAT_XENFS=y
CONFIG_XEN_SYS_HYPERVISOR=y
CONFIG_XEN_XENBUS_FRONTEND=y
CONFIG_XEN_GNTDEV=y
CONFIG_XEN_GRANT_DEV_ALLOC=y
CONFIG_SWIOTLB_XEN=y
CONFIG_XEN_TMEM=m
CONFIG_XEN_PCIDEV_BACKEND=y
CONFIG_XEN_PRIVCMD=y
CONFIG_XEN_HAVE_PVMMU=y
——

PS: I think I’ll just switch to KVM...

[Comment 1 Yixun Lan 2014-04-25 14:44:05 UTC]

It would be great if you can provide
1) emerge --info app-emulation/xen 
2) full kernel config file

don't know the exact reason, but from "page allocation failure", which means it unable to load kernel module due to fail to allocate vm memory. 

how much memory do you reserve for dom0?
try to switch to openrc? did systemd consume too much memory?

[Comment 2 Another Mortal 2014-04-29 08:43:57 UTC]

Created attachment 376008 [details]
emerge —info xen

[Comment 3 Another Mortal 2014-04-29 08:44:51 UTC]

Created attachment 376010 [details]
config-3.14.1-gentoo

[Comment 4 Another Mortal 2014-04-29 08:45:15 UTC]

Created attachment 376012 [details]
config-3.14.1-hardened

[Comment 5 Another Mortal 2014-04-29 08:47:03 UTC]

The output from ‘emerge —info xen’ and the kernel config files are now attached.

> how much memory do you reserve for dom0?

4GB

> try to switch to openrc? did systemd consume too much memory?

This box uses openrc already.
Any trace of systemd must be due to udev.

[Comment 6 Ian Delaney (RETIRED) 2014-06-22 01:05:33 UTC]

almost 2 months now, a.m.  what's ths current status?

[Comment 7 Another Mortal 2014-07-18 12:41:47 UTC]

No idea.  Sorry...
I did switch to KVM.
Got fed up with all
the cruft around Xen.

Good luck!