Bug 486863

Created attachment 332861 [details]
Para-virt kernel output / panic text

Description of problem:
A 32-bit para-virt guest (RHEL v5.3) can be installed and runs correctly on a 64-bit (RHEL v5.3) HP ProLiant DL380-G5 (2x Xeon X5450, 12GB RAM) but the same VM fails to install (or when the disk image is copied from the working server boot) on a 64-bit (RHEL v5.3) HP ProLiant DL580-G5 (4x Xeon X7350, 128GB RAM). At kernel startup either both installation or booting of the para-virt guest on the non-working hypervisor the guest errors with  "kernel BUG at include/linux/mm.h:310!"  and the kernel panics very shortly after booting (full output attached). For reference a 64-bit para-virt guest (RHEL v5.3) as well as HVM guests (32-bit, RHEL v4.6) operate fine on the hosting server having issues with the 32-bit para-virt guest. I am able to reproduce this on two sets of matching hardware and software. I have tried raising and lowering the memory specified in the config files (or virt-install command-lines) and dropping from 2 VCPUs to 1 VCPU with no success. This does occur with SAN hosted volume groups or disk-image based stored. It also occurs when the hosting DL580 has no other guests present. I am able to see from our RHN Proxy logs that virt-install is correct retrieving the xen kernel and initrd from the installation location provided.

Version-Release number of selected component (if applicable):

Para-virt guest kernel:           kernel-xen-2.6.18-128.el5 (also tried 2.6.18-128.1.1)
Hypervisor kernel (both servers): kernel-xen-2.6.18-128.1.1.el5
Xen version (both servers):       xen-3.0.3-80.el5

How reproducible:
Matching virt-install command-lines carried out on 2x DL380-G5s (one with 12GB memory, one with 16GB memory, both with 2x Xeon 54xx processors) worked fine. The same command-line tried on 2x DL580-G5s (both with 128GB memory, both with 4x Xeon 73xx processors) caused kernel panics on guest startup. This included when a pre-installed and working guest was imported (ie. disk image was copied and booted) from the working systems.

Steps to Reproduce:
virt-install -n misap5u4 --nographics -r 4096 --vcpus=2 -f /dev/vms-vg1/misap5u4-hda -m '00:00:XX:XX:XX:XX' --bridge=xenbr3 -p -l 'http://XX.XX.XX.XX/install/software/rhel5-u3/i386/' -x 'ic=as,5,3,i386,mis,apvm, nofb text noipv6 ks=http://XX.XX.XX.XX/install/scripts/dev/rhel4-server/ks/as5-i386-u3.ks'

The exact specifics of re-producibility as you will gather from the desription appear to be purely based on the hosting hardware (perhaps memory or differences between the 54xx and 73xx CPUs).

Actual results:
A 32-bit para-virt guest can be installed and operated on a smaller hosting server but not a larger platform.

Expected results:
Matching 32-bit para-virt hosting on both (sets of) hosting servers.

Additional info:
The hosting servers have been booted with and without selinux. The DL380s use the Xen parameter  "dom0_mem=512M", the DL580s use "dom0_mem=768M". I have been through the contents of xend.log, domain-builder-ng.log, the output from  xm dmesg  on both servers and found little to differentiate the systems. I can provide them on request.