Re: dom0 panics when copying large file

[Christoph Egger <Christoph_Egger%gmx.de@localhost>]

Julio Merino wrote:
> 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?

When you are in ddb, what does 'show register' print ?

What is the output of

gdb netbsd.gdb
(gdb) list *(pmap_kenter_pa+0x169)

Christoph