Re: [PATCH] fix segfault in xl migrate --debug

[Ian Campbell <Ian.Campbell@citrix.com>]

On Wed, 2014-11-26 at 21:19 +0000, Andrew Cooper wrote:
> On 26/11/2014 19:54, M A Young wrote:
> 
> > If differences are found during the verification phase of xl migrate
> > --debug then it is likely to crash with a segfault because the
> > bogus 
> > pagebuf->pfn_types[pfn] is used in a print statement instead of
> > pfn_type[pfn] . 
> > 
> > Signed-off-by: Michael Young <m.a.young@durham.ac.uk>
> > 
> > 
> > 
> 
> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Ian Campbell <ian.campbell@citrix.com>

Needs a release ack if this is to be for 4.5, Konrad CCd.

On the one hand this fixes an issue which is only present if you enable
debug/verify mode, so it's not that critical. On the other hand it only
touches code which is used if you enable debug/verify mode, so it's not
that risky.

I'm inclined towards the apply it for 4.5 end of the scale...

> 
> > xl migrate --debug can segfault because pagebuf->pfn_types[pfn] is
> > used in a print statement instead of pfn_type[pfn] 
> > 
> > --- xen-4.5.0-rc1/tools/libxc/xc_domain_restore.c.orig	2014-10-24 15:22:40.000000000 +0100
> > +++ xen-4.5.0-rc1/tools/libxc/xc_domain_restore.c	2014-11-25 21:01:16.604081467 +0000
> > @@ -1404,7 +1404,7 @@
> >                  int v;
> >  
> >                  DPRINTF("************** pfn=%lx type=%lx gotcs=%08lx "
> > -                        "actualcs=%08lx\n", pfn, pagebuf->pfn_types[pfn],
> > +                        "actualcs=%08lx\n", pfn, pfn_type[pfn],
> >                          csum_page(region_base + i * PAGE_SIZE),
> >                          csum_page(buf));
> >  
>