Re: [Xen-devel] [BUGFIX][PATCH v2 2/5] dbg_rw_guest_mem: need to call put_gfn in error path.

[Don Slutz <dslutz@xxxxxxxxxxx>]

On 01/08/14 03:36, Jan Beulich wrote:
> > > > On 08.01.14 at 01:25, Don Slutz <dslutz@xxxxxxxxxxx> wrote:
> > --- a/xen/arch/x86/debug.c
> > +++ b/xen/arch/x86/debug.c
> > @@ -63,10 +63,17 @@ dbg_hvm_va2mfn(dbgva_t vaddr, struct domain *dp, int toaddr,
> >       if ( p2m_is_readonly(gfntype) && toaddr )
> >       {
> >           DBGP2("kdb:p2m_is_readonly: gfntype:%x\n", gfntype);
> > -        return INVALID_MFN;
> > +        mfn = INVALID_MFN;
> >       }
> >   
> >       DBGP2("X: vaddr:%lx domid:%d mfn:%lx\n", vaddr, dp->domain_id, mfn);
> With the flow change above, this should be moved into an "else"
> to the earlier "if".
Ok.  I have done this and tested it.  (v3 attached).

Note: this means that patch v2 3/5 will not cleanly apply.  I am in the process 
of fixing and testing v3 of that.  Andrew Cooper in

http://lists.xen.org/archives/html/xen-devel/2014-01/msg00595.html

Says that this one patch "should be included ASAP"; which is why I am sending 
this 1st.

I did not add:

Acked-by: Mukesh Rathor ...

Even though my understanding is that I could have (please let me know if this 
is wrong) based on:

http://lists.xen.org/archives/html/xen-devel/2014-01/msg00601.html

since the v3 change is very minor (like a comment change).  This is because 
DBGP2:

#define DBGP2(...) ((void)0)

does nothing.  And if changed to do something, the file fails to compile 
without more changes (I.E. patch 3/5).  Even though I knew this does nothing I 
has compiled and run this code.


I did change the author to "Andrew Cooper <andrew.cooper3@xxxxxxxxxx>" since he 
provided most of this change. (see

http://lists.xen.org/archives/html/xen-devel/2014-01/msg00631.html

)  Not sure that is correct since we have now both made changes.

   -Don Slutz



> Jan
>
> > +
> > +    if ( mfn == INVALID_MFN )
> > +    {
> > +        put_gfn(dp, *gfn);
> > +        *gfn = INVALID_GFN;
> > +    }
> > +
> >       return mfn;
> >   }

Attachment: 0001-dbg_rw_guest_mem-need-to-call-put_gfn-in-error-path.patch
Description: Text Data

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