Re: [Xen-devel] [Patch] Call sched_destroy_domain before cpupool_rm_domain.

[Juergen Gross <juergen.gross@xxxxxxxxxxxxxx>]

On 07.11.2013 10:37, Jan Beulich wrote:
> > > > On 07.11.13 at 10:09, Juergen Gross <juergen.gross@xxxxxxxxxxxxxx> wrote:
> > On 07.11.2013 08:39, Jan Beulich wrote:
> > > > > > On 05.11.13 at 06:59, Juergen Gross <juergen.gross@xxxxxxxxxxxxxx> wrote:
> > > > On 04.11.2013 16:22, Nate Studer wrote:
> > > > > On 11/4/2013 4:58 AM, Juergen Gross wrote:
> > > > > > All other schedulers will just call xfree() for the domain specific data
> > (and
> > > > > > may be update some statistic data, which is not critical).
> > > > > The credit and credit2 schedulers do a bit more than that in their
> > free_domdata
> > > > > functions.
> > > > Sorry, got not enough sleep on the weekend ;-)
> > > >
> > > > I checked only 4.1 and 4.2 trees. There only xfree of the domain data is
> > > > done.
> > > >
> > > > > The credit scheduler frees the node_affinity_cpumask contained in the domain
> > > > > data and the credit2 scheduler deletes a list element contained in the
> > domain
> > > > > data.  Since with this bug they are accessing structures that do not belong
> > to
> > > > > them, bad things happen.
> > > > So the patch would be subject to a 4.3 backport, I think.
> > > Hmm, I'm slightly confused: credit2's free_domdata has always been
> > > doing more than just xfree() afaict, and hence backporting is either
> > > necessary uniformly or (taking into account that it was made clear
> > > that arinc doesn't work with CPU pools anyway so far) not at all.
> > >
> > > Please clarify.
> > Okay, I assumed only "production ready" features are to be taken into
> > account
> > for a backport. And credit2 is clearly not in this state, or am I wrong?
> You aren't, but is arinc production ready? I wouldn't think so
> simply based on it not working with CPU pools. And then the
> backporting question would become mute.
No, it doesn't. The following statement should have made that clear:

> > A 4.3 backport should be considered in any case, as sedf and credit
> > schedulers
> > behave differently in free_domdata, and both are "production ready".
If you have credit as default scheduler and use sedf in a cpupool, destroying
a domain in the cpupool with sedf will use the credit free_domdata routine,
leading to an error in 4.3 when calling free_cpumask_var().


Juergen

--
Juergen Gross                 Principal Developer Operating Systems
PBG PDG ES&S SWE OS6                   Telephone: +49 (0) 89 62060 2932
Fujitsu                                   e-mail: juergen.gross@xxxxxxxxxxxxxx
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