Re: Bug#599089: linux-image-2.6.32-5-xen-686: Kernel Panics when using NFS from DomU to Dom0

[Jeremy Fitzhardinge <jeremy@goop.org>]

 On 10/05/2010 11:22 AM, Ian Campbell wrote:
> On Tue, 2010-10-05 at 09:54 -0700, Jeremy Fitzhardinge wrote: 
>> On 10/05/2010 02:52 AM, Ian Campbell wrote:
>>> On Tue, 2010-10-05 at 10:47 +0100, Ian Campbell wrote:
>>>> In addition to the kernel logging of the error I get this from the
>>>> hypervisor:
>>>> (XEN) mm.c:2062:d0 Error pfn 16d99: rd=ffff83011fefa000,
>>>> od=0000000000000000, caf=180000000000000, taf=0000000000000000
>>>> (XEN) mm.c:658:d0 Could not get page ref for pfn 16d99
>>>> (XEN) mm.c:3621:d0 Could not get page for mach->phys update
>>> Adding a bit more logging to the kernel I get:
>>> gnttb_copy_grant_page old c22ebcd8 P:0x1ec8e M:0xc499d F:0x41000000
>>> gnttb_copy_grant_page new c2324ce0 P:0x1fe18 M:0x11cd32 F:0x40000000
>>> (XEN) mm.c:2062:d0 Error pfn 1cd32: rd=ffff83011fefa000, od=0000000000000000, caf=180000000000000, taf=0000000000000000
>>> (XEN) mm.c:658:d0 Could not get page ref for pfn 1cd32
>>> (XEN) mm.c:3621:d0 Could not get page for mach->phys update
>>>
>>> Notice how MFN 0x11cd32 has become 0x1cd32 by the time it gets to the
>>> hypervisor!
>> Oy, more of these.  It might be better to use PFN_PHYS().
> I thought there ought to be a helper but couldn't find one, PFN_PHYS
> sounds like a good bet, unless we want to alias it as MFN_MACH or
> something?

Doesn't really seem worth it, unless phys_addr_t ends up not being large
enough for a machine address.  But I think we rely on that pretty
heavily anyway.

I've committed it with that change.

    J