dom0 panics when copying large file

[Julio Merino <jmmv84%gmail.com@localhost>]

Hello,

I have NetBSD 5.99.22 amd64 running on a 4-core, 8gb machine.  I can
reproducibly panic the machine by scp'ing an ISO image into it, and it
seems to always crash at about 80% of the copy (2.8GB, but never in
the exact same place).

This happens with a XEN3_DOM0 kernel (xen 3.3), but not with a GENERIC
one.  There are no domUs: the file is being copied froma remote
machine into the dom0, which has 6gb of ram and 8gb of swap.

The trace goes like this:

kernel: page fault trap, code=0
Stopped in pid 41.1 (scp) at netbsd:pmap_kenter_pa+0x169: movq 0(%rax),%rsi
pmap_kenter_pa() at netbsd:pmap_kenter_pa+0x169
ubc_alloc() at netbsd:ubc_alloc+0x289
ubc_iomove() at netbsd:ubc_uiomove+0xc0
ffs_write() at netbsd:ffs_write+0x2a4
VOP_WRITE() at netbsd:VOP_WRITE+0x2d
vn_write() at netbsd:vn_write+0xc0
dofilewrite() at netbsd:dofilewrite+0x74
sys_write() at netbsd:sys_write+0x6e
syscall() at netbsd:syscal+0xa8

WAPBL is not involved.

Also, unrelated, but annoying: I cannot get a crash dump.  When the
machine panics, it doesn't save a coredump.  The dom0 has 6gb of ram
assigned, the machine has a total of 8gb and the swap partition is
8gb, so the dump should fit.

Any ideas?

Thanks

-- 
Julio Merino