port-xen/45158: Xen Kernel panics when restarting DomU (Problem with vnd detach?)

[roger.pau%entel.upc.edu@localhost]

>Number:         45158
>Category:       port-xen
>Synopsis:       Xen Kernel panics when restarting DomU (Problem with vnd 
>detach?)
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-xen-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jul 19 08:30:00 +0000 2011
>Originator:     Roger Pau Monne
>Release:        5.99.55
>Organization:
UPC
>Environment:
NetBSD loki 5.99.55 NetBSD 5.99.55 (XEN3_DOM0) #0: Mon Jul 18 20:18:34 CEST 
2011  royger@loki:/usr/obj/sys/arch/amd64/compile/XEN3_DOM0 amd64
>Description:
Sometimes when restarting a domu I get the following panic (kernel compiled 
with diagnostic option):

xbd backend: detach device vnd1d for domain 6
xbd backend: detach device vnd0d for domain 6
panic: kernel diagnostic assertion "vp == vp->v_specnode->sn_dev->sd_bdevvp" 
failed: file "/usr/src/sys/miscfs/specfs/spec_vnops.c", line 1013
cpu0: Begin traceback...
copyright() at ffffffff80988d1d
uvm_fault(0xffffffff80c8d5a0, 0xffffa00000000000, 1) -> e
fatal page fault in supervisor mode
trap type 6 code 0 rip ffffffff8022d577 cs e030 rflags 10246 cr2  
ffffa00000000008 cpl 0 rsp ffffa0002ae29240
Skipping crash dump on recursive panic
panic: trap
Faulted in mid-traceback; aborting...rebooting...
(XEN) Domain 0 shutdown: rebooting machine.
>How-To-Repeat:
Start and stop a domu several times. I think the same should happen when 
mounting an unmouting and image several times using vnconfig.
>Fix:
Compile without diagnostic option?