[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-ppc] [PATCH] spapr: fix write-past-end-of-array error in cpu c
From: |
David Gibson |
Subject: |
Re: [Qemu-ppc] [PATCH] spapr: fix write-past-end-of-array error in cpu core device init code |
Date: |
Tue, 28 Jun 2016 16:24:22 +1000 |
User-agent: |
Mutt/1.6.1 (2016-04-27) |
On Tue, Jun 28, 2016 at 07:24:16AM +0200, Greg Kurz wrote:
> On Tue, 28 Jun 2016 12:55:07 +1000
> David Gibson <address@hidden> wrote:
>
> > On Mon, Jun 27, 2016 at 06:28:15PM +0200, Greg Kurz wrote:
> > > This fixes a potential QEMU crash introduced by commit 3b542549661.
> > >
> > > Signed-off-by: Greg Kurz <address@hidden>
> > > ---
> > > hw/ppc/spapr_cpu_core.c | 3 +--
> > > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > Ugh. The existing code is wrong in the case where the failure happens
> > after the loop.
> >
> > But this version is wrong in the case it happens during the loop - it
> > will fail to clean up the last object created.
> >
>
> Hmm... unless I'm missing something, if object_property_add_child() fails to
> add object i, we don't want to unparent it, and we should start rollback
> at index i-1.
Good point, my mistake. I'll apply this fix.
>
> Another weirdness is that I see no rollback for the object_child_foreach()
> loop: in case of failure, we will unparent realized objects... is it
> okay ?
Um.. I have no idea. Bharata? Alex?
>
> > > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> > > index 3a5da09b9902..8b802a6fcf0b 100644
> > > --- a/hw/ppc/spapr_cpu_core.c
> > > +++ b/hw/ppc/spapr_cpu_core.c
> > > @@ -309,10 +309,9 @@ static void spapr_cpu_core_realize(DeviceState *dev,
> > > Error **errp)
> > > }
> > >
> > > err:
> > > - while (i >= 0) {
> > > + while (--i >= 0) {
> > > obj = sc->threads + i * size;
> > > object_unparent(obj);
> > > - i--;
> > > }
> > > g_free(sc->threads);
> > > error_propagate(errp, local_err);
> > >
> >
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
signature.asc
Description: PGP signature