>Number:         35050
>Category:       kern
>Synopsis:       xen3_dom0 kernel crashed when I try to use NFS mounted image for xen3_domu netbsd.
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Nov 13 23:10:01 +0000 2006
>Originator:     Jam
>Release:        NetBSD 4.99.3
>Organization:
personal
	
>Environment:
System: NetBSD fs 4.99.3 NetBSD 4.99.3 (XEN3_DOM0) #2: Tue Oct 31 22:37:16 JST 2006  jam@pixy:/usr/obj/mnt/raid/netbsd/current/src/sys/arch/i386/compile/XEN3_DOM0 i386
Architecture: i386
Machine: i386
>Description:
	I tried to use NFS mounted netbsd image for XEN3_DOMU.
	It crashs DOM0 kernel.  Following dialogue is taken
	from serial console of DOM0 kernel.  I created DOMU and
	ran netbsd on it.  When it tried to mount root file
	system, DOM0 kernel crashed.
	
fs# xm create -c ./netbsd1nfs
Using config file "./netbsd1nfs".
xvif1.0: Ethernet address aa:00:00:51:02:f0
xbd backend: attach device vnd0d (size 1048576) for domain 1
xbd backend: attach device wd0e (size 107475921) for domain 1
/usr/pkg/lib/python2.4/xmllib.py:9: DeprecationWarning: The xmllib module is obsolete.  Use xml.sax instead.
  warnings.warn("The xmllib module is obsolete.  Use xml.sax instead.", DeprecationWarning)
Started domain netbsd1
Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 4.99.3 (XEN3_DOMU) #2: Tue Oct 31 22:38:30 JST 2006
	jam@pixy:/usr/obj/mnt/raid/netbsd/current/src/sys/arch/i386/compile/XEN3_DOMU
total memory = 256 MB
avail memory = 247 MB
mainbus0 (root)
hypervisor0 at mainbus0
vcpu0 at hypervisor0: (uniprocessor)
vcpu0: Intel Celeron (686-class), 1403.18 MHz, id 0x6b4
vcpu0: features 383f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR>
vcpu0: features 383f9ff<PGE,MCA,CMOV,PAT,PSE36,MMX>
vcpu0: features 383f9ff<FXSR,SSE>
vcpu0: I-cache 16 KB 32B/line 4-way, D-cache 16 KB 32B/line 4-way
vcpu0: L2 cache 256 KB 32B/line 8-way
vcpu0: ITLB 32 4 KB entries 4-way, 2 4 MB entries fully associative
vcpu0: DTLB 64 4 KB entries 4-way, 8 4 MB entries 4-way
vcpu0: 8 page colors
debug virtual interrupt using event channel 3
xenbus0 at hypervisor0: Xen Virtual Bus Interface
xencons0 at hypervisor0: Xen Virtual Console Driver
xencons0: console major 143, unit 0
xencons0: using event channel 2
npx0 at hypervisor0: using exception 16
Xen clock: using event channel 4
crypto: assign driver 0, flags 2
crypto: driver 0 registers alg 1 flags 0 maxoplen 0
crypto: driver 0 registers alg 2 flags 0 maxoplen 0
crypto: driver 0 registers alg 3 flags 0 maxoplen 0
crypto: driver 0 registers alg 4 flags 0 maxoplen 0
crypto: driver 0 registers alg 5 flags 0 maxoplen 0
crypto: driver 0 registers alg 17 flags 0 maxoplen 0
crypto: driver 0 registers alg 6 flags 0 maxoplen 0
crypto: driver 0 registers alg 7 flags 0 maxoplen 0
crypto: driver 0 registers alg 15 flags 0 maxoplen 0
crypto: driver 0 registers alg 8 flags 0 maxoplen 0
crypto: driver 0 registers alg 16 flags 0 maxoplen 0
crypto: driver 0 registers alg 9 flags 0 maxoplen 0
crypto: driver 0 registers alg 10 flags 0 maxoplen 0
crypto: driver 0 registers alg 13 flags 0 maxoplen 0
crypto: driver 0 registers alg 14 flags 0 maxoplen 0
crypto: driver 0 registers alg 11 flags 0 maxoplen 0
crypto: driver 0 registers alg 18 flags 0 maxoplen 0
raidattach: Asked for 8 units
Kernelized RAIDframe activated
xenbus0: using event channel 1
xbd0 at xenbus0 id 3: Xen Virtual Block Device Interface
xbd0: using event channel 5
xbd backend 0x3 for domain 1 using event channel 17
xbd1 at xenbus0 id 12: Xen Virtual Block Device Interface
xbd1: using event channel 6
xbd backend 0xc for domain 1 using event channel 18
xennet0 at xenbus0 id 0: Xen Virtual Network Interface
xennet0: MAC address aa:00:00:50:02:f0
xennet0: using event channel 7
xbd0: 512 MB, 512 bytes/sect x 1048576 sectors
xbd1: 52478 MB, 512 bytes/sect x 107475921 sectors
Searching for RAID components...
boot device: xbd0
root on xbd0a dumps on xbd0b
mountroot: trying lfs...
mountroot: trying ffs...
root file system type: ffs
init: copying out path `/sbin/init' 11
Tue Nov 14 07:48:16 JST 2006
swapctl: adding /dev/xbd0b as swap device at priority 0
Checking for botched superblock upgrades: done.
Starting file system checks:
/dev/rxbd0a: file system is clean; not checking
panic: kernel diagnostic assertion "pg != NULL" failed: file "../../../../uvm/uvm_pager.c", line 499
Stopped in pid 376.1 (nfsio) at netbsd:cpu_Debugger+0x4:        popl    %ebp
db> trace
cpu_Debugger(c085361a,c9187ab8,6,0,0) at netbsd:cpu_Debugger+0x4
panic(c08b1df0,c081b625,c082ec72,c082fb92,1f3) at netbsd:panic+0x155
__assert(c081b625,c082fb92,1f3,c082ec72,c9187b1c) at netbsd:__assert+0x2e
uvm_pageratop(c8769800,1,0,0,1e070000) at netbsd:uvm_pageratop+0x63
nfs_doio_write(c9187bf0,0,0,0,0) at netbsd:nfs_doio_write+0xda
nfs_doio(c0c2dd14,320,c082c1b4,0,c0944400) at netbsd:nfs_doio+0x1c0
nfssvc_iod(c864d1bc,246,0,c010200d,c864d1bc) at netbsd:nfssvc_iod+0xce
start_nfsio(c864d1bc,0,c01001e7,c01001df,c01001e7) at netbsd:start_nfsio+0x13
db> sync

	Sync didn't dump.  System hung.

>How-To-Repeat:
	This happens whenever I tried to use NFS mounted image for
	DOMU kernel.
>Fix:
	Not sure.

>Unformatted:
 	Source codes are taken at 2006/11/12.
 	I compiled new XEN3 kernels using default configuration files.