Re: kern/57002: Starting NetBSD in a HVM DomU crashes Dom0

[Brad Spencer <brad%anduin.eldar.org@localhost>]

Hauke Fath <hf%spg.tu-darmstadt.de@localhost> writes:

>>Number:         57002
>>Category:       kern
>>Synopsis:       Starting NetBSD in a HVM DomU crashes Dom0
>>Confidential:   no
>>Severity:       critical
>>Priority:       high
>>Responsible:    kern-bug-people
>>State:          open
>>Class:          sw-bug
>>Submitter-Id:   net
>>Arrival-Date:   Fri Sep 09 17:05:00 +0000 2022
>>Originator:     Hauke Fath
>>Release:        NetBSD 9.3
>>Organization:
> Technische Universitaet Darmstadt
>>Environment:
> 	
> 	
> System: NetBSD Treffauer 9.3 NetBSD 9.3 (FEUERKOGEL_DOM0-$Revision$) #0: Tue Aug 9 15:30:14 CEST 2022 hf@Hochstuhl:/var/obj/netbsd-builds/9/amd64/sys/arch/amd64/compile/FEUERKOGEL_DOM0 amd64
> Architecture: x86_64
> Machine: amd64
> % pkg_info | grep xen
> xenkernel413-4.13.4nb1 Xen 4.13.x Kernel
> xentools413-4.13.4nb6 Userland Tools for Xen 4.13.x
> %
>
>>Description:
>
> 	Starting a Xen HVM DomU from a NetBSD 9 install iso crashes
> 	the Dom0 with
>
> [...]
> [ 296.6180677] xbd backend: attach device vg0-hazel_root (size 20971520) for domain 2
> [ 300.3380380] pmap_unwire: wiring for pmap 0xffffb48004fcf060 va 0x7c0c00107000 did not change!
> [ 334.8277708] pmap_unwire: wiring for pmap 0xffffb48004fcf060 va 0x7c0c00151000 did not change!
> [ 334.8277708] pmap_unwire: wiring for pmap 0xffffb48004fcf060 va 0x7c0c00152000 did not change!
> [ 334.8277708] pmap_unwire: wiring for pmap 0xffffb48004fcf060 va 0x7c0c00153000 did not change!
> [ 337.3877490] pmap_unwire: wiring for pmap 0xffffb48004fcf060 va 0x7c0bf5dfc000 did not change!
> [ 337.3877490] panic: kernel diagnostic assertion "pg->wire_count != 0" failed: file "/u/netbsd-9/src/sys/uvm/uvm_page.c", line 1618 
> [ 337.3877490] cpu0: Begin traceback...
> [ 337.3977488] vpanic() at netbsd:vpanic+0x143
> [ 337.3977488] kern_assert() at netbsd:kern_assert+0x48
> [ 337.3977488] uvm_pageunwire() at netbsd:uvm_pageunwire+0x81
> [ 337.3977488] uvm_fault_unwire_locked() at netbsd:uvm_fault_unwire_locked+0x135
> [ 337.3977488] uvm_fault_unwire() at netbsd:uvm_fault_unwire+0x29
> [ 337.3977488] physio_done() at netbsd:physio_done+0x77
> [ 337.3977488] workqueue_worker() at netbsd:workqueue_worker+0xce
> [ 337.3977488] cpu0: End traceback...
>
> [ 337.3977488] dumping to dev 18,1 (offset=33554431, size=0): not possible
> [ 337.3977488] rebooting...
> (XEN) Hardware Dom0 shutdown: rebooting machine
> (XEN) Resetting with ACPI MEMORY or I/O RESET_REG.[-- hf@localhost detached -- Fri Sep  9 18:44:46 2022]
>
>
> 	
>>How-To-Repeat:
> 	
>
> 	Set up a Xen DomU HVM configuration with an lvm disk device and a
> 	NetBSD 9 iso image. Have it render to VNC.
>
> 	Watch the boot freeze while probing the disk device, then
> 	watch the Xen host crash and reboot.
>
> 	The DomU configuration is
>
> type = "hvm"
> firmware = "seabios"
> kernel = "/usr/pkg/libexec/xen/boot/hvmloader"
> memory = 1024
> vcpus = 1
> acpi = 1
> name = "Hazel"
> ioemu = [ 'mac=00:16:3e:NN:MM:OO, bridge=bridge1' ]
> disk = [ 'backendtype=phy, vdev=hda, target=/dev/mapper/vg0-hazel_root',
>          'vdev=hdb, devtype=cdrom, target=/var/tmp/NetBSD-9.0_STABLE-amd64.iso']
> vga="cirrus"
> vnc=1
> vnclisten="127.0.0.1"
> vncdisplay=10
> serial = "pty"
>
>>Fix:
> 	
> 	Yes, please.
>
>>Unformatted:
>  	
>  	


I saw this too with Xen 4.15 with a 9.2_STABLE DOM0 and mentioned this
all in a post on port-xen.  The problem goes away for me if I use file
backstore and not LVM LVs.  Further, I do not always get a immediate
crash, but the DOM0 *WILL* panic at some point usually in the 24 hours
or so after I messed with a HVM that trips this.



-- 
Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS - http://anduin.eldar.org