port-xen/38699: NetBSD-amd64 Xen dom0 with 4.5GB memory panics

[tron%zhadum.org.uk@localhost]

>Number:         38699
>Category:       port-xen
>Synopsis:       NetBSD-amd64 Xen dom0 with 4.5GB memory panics
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-xen-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon May 19 20:45:00 +0000 2008
>Originator:     tron%zhadum.org.uk@localhost
>Release:        NetBSD 4.99.63
>Organization:
Matthias Scheler                                  http://zhadum.org.uk/
>Environment:
System: NetBSD lyssa.zhadum.org.uk 4.99.63 NetBSD 4.99.63 (XEN3_DOM0) #0: Sun 
May 18 13:34:14 BST 2008  
tron%lyssa.zhadum.org.uk@localhost:/src/sys/compile/XEN3_DOM0 amd64
Architecture: x86_64
Machine: amd64
>Description:
When I boot a Xen dom0 kernel on my NetBSD-amd64 system with 4.5GB of
memory assigned to it the kernel panics as soon as any serious amount
of filesystem I/O takes place:

uvm_fault(0xffffffff80b37a20, 0xffffffff81400000, 1) -> e
kernel: page fault trap, code=0
Stopped in pid 325.1 (tar) at   netbsd:pmap_kenter_pa+0x163:    movq    
0(%rax),%rsi
pmap_kenter_pa() at netbsd:pmap_kenter_pa+0x163
uvm_pagermapin() at netbsd:uvm_pagermapin+0x189
genfs_getpages() at netbsd:genfs_getpages+0xc2f
VOP_GETPAGES() at netbsd:VOP_GETPAGES+0x42
ufs_balloc_range() at netbsd:ufs_balloc_range+0xed
ffs_write() at netbsd:ffs_write+0x7c3
VOP_WRITE() at netbsd:VOP_WRITE+0x2a
vn_write() at netbsd:vn_write+0xce
dofilewrite() at netbsd:dofilewrite+0x7c
sys_write() at netbsd:sys_write+0x72
syscall() at netbsd:syscall+0x98
ds          0x6
es          0
fs          0xffff
gs          0
rdi         0xffffa0004a983000
rsi         0xe67d5000
rbp         0xffffa000528b6700
rbx         0xe67d5
rdx         0x7f8000000000
rcx         0x6
rax         0xffffffff81400ea8
r8          0xffffffff80adeb80  cpu_info_primary
r9          0
r10         0xffffa000528b65d0
r11         0x7f8000000000
r12         0x3
r13         0x7fd000254c18
r14         0xffffa000528b6858
r15         0xffffa0004a983000
rip         0xffffffff804cdcc3  pmap_kenter_pa+0x163
cs          0xe030
rflags      0x10282
rsp         0xffffa000528b66d0
ss          0xe02b
netbsd:pmap_kenter_pa+0x163:    movq    0(%rax),%rsi

Here is the backtrace:

pmap_kenter_pa() at netbsd:pmap_kenter_pa+0x163
uvm_pagermapin() at netbsd:uvm_pagermapin+0x189
genfs_getpages() at netbsd:genfs_getpages+0xc2f
VOP_GETPAGES() at netbsd:VOP_GETPAGES+0x42
ufs_balloc_range() at netbsd:ufs_balloc_range+0xed
ffs_write() at netbsd:ffs_write+0x7c3
VOP_WRITE() at netbsd:VOP_WRITE+0x2a
vn_write() at netbsd:vn_write+0xce
dofilewrite() at netbsd:dofilewrite+0x7c
sys_write() at netbsd:sys_write+0x72
syscall() at netbsd:syscall+0x98

>How-To-Repeat:
Boot a NetBSD-amd64 Xen dom0 with the following grub config:

title Xen 3.1 / NetBSD (hda0, serial)
  root(hd0,0)
  kernel (hd0,a)/xen.gz dom0_mem=4718592 com1=115200,8n1
  module (hd0,a)/netbsd-XEN3_DOM0 bootdev=wd0a ro console=ttyS0 

>Fix:
None provided.