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Re: [Qemu-devel] [PATCH] spapr: fix write-past-end-of-array error in cpu
Bharata B Rao
Re: [Qemu-devel] [PATCH] spapr: fix write-past-end-of-array error in cpu core device init code
Tue, 28 Jun 2016 13:30:47 +0530
On Tue, Jun 28, 2016 at 04:24:22PM +1000, David Gibson wrote:
> 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?
This is similar to how device_add code recovers when there is failure
during realize. So I think object_unparent() should be fine. Only other
thing I need to verify is whether an additional object_unref() is needed