Re: Xen-4.3 and -unstable regression from changeset "numa-sched: leave node-affinity alone if not in 'auto' mode"

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 28/11/13 12:31, Andrew Cooper wrote:
> Hello,
>
> I have recently positivly identified
> b54a623efbcf5bff25c55117add1b4427b4e2f1b as causing a boot failure.
>
> Serial log is attached.  The crash is completely deterministic, and is
> from an IBM xSeries 3530 M4 server.
>
> Given the crash and bad patch, I suspect it is more to do with the
> NUMA/memory layout than the specifics of the server.
>
> Dario: Being your patch, do you have any ideas?
>
> George: Regarding the release, if a fix cant easily be found, it might
> be worth considering reverting the change.
>
> ~Andrew

Following some further debugging, this is rather more complicated than I
initially thought.

There is some form of memory corruption; depending on which exact
underlying changeset I base the XenServer patch queue on, or which pages
are present in the queue, I get crashes in different locations,
including faults from mis-aligned instructions including stack traces
which are completely bogus.

The saving grace is that the crashes appear to be completely
deterministic for a given binary.  (although this sever is slower than
treacle to boot)

~Andrew