Re: Linux Xen PV CPA W^X violation false-positives

[Juergen Gross <jgross@xxxxxxxx>]

On 08.04.24 12:22, Anthony PERARD wrote:
> On Thu, Mar 28, 2024 at 02:00:14PM +0100, Jürgen Groß wrote:
> > Hi Jason,
> >
> > On 28.03.24 02:24, Jason Andryuk wrote:
> > > On Wed, Mar 27, 2024 at 7:46 AM Jürgen Groß <jgross@xxxxxxxx> wrote:
> > > > On 24.01.24 17:54, Jason Andryuk wrote:
> > > > > +
> > > > > +                     return new;
> > > > > +             }
> > > > > +     }
> > > > > +
> > > > >         end = start + npg * PAGE_SIZE - 1;
> > > > >         WARN_ONCE(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx 
> > > > > - 0x%016lx PFN %lx\n",
> > > > >                   (unsigned long long)pgprot_val(old),
> > > > Jason, do you want to send a V2 with your Signed-off, or would you like me to
> > > > try upstreaming the patch?
> > > Hi Jürgen,
> > >
> > > Yes, please upstream your approach.  I wasn't sure how to deal with
> > > it, so it was more of a bug report.
> > The final solution was a bit more complicated, as there are some
> > corner cases to be considered. OTOH it is now complete by looking
> > at all used translation entries.
> >
> > Are you able to test the attached patch? I don't see the original
> > issue and can only verify the patch doesn't cause any regression.
> >
> >
> > Juergen
> Hi Jürgen,
>
> I gave a try to the patch in this email with osstest, and I can't find a
> single "CPA detected W^X violation" log entry, when there's seems to be
> many in osstest in general, from dom0 it seems as it's on the host
> serial console usually.
>
> http://logs.test-lab.xenproject.org/osstest/logs/185252/
>
> If you look in several "serial-$host.log*" files, there will be the
> "CPA detected" message, but they happen on previous test run.
>
> I did an other smaller run before this one, and same thing:
> http://logs.test-lab.xenproject.org/osstest/logs/185186/
>
> And this other run as well, which I failed to setup properly with lots
> of broken, but no failure due to the patch and I can't find any "CPA
> detected" messages.
> http://logs.test-lab.xenproject.org/osstest/logs/185248/
>
> I hope that helps?
Yes, it does. Thanks for testing.


Juergen

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