Re: [Qemu-devel] [PATCH v2 2/2] memory: fix possible NULL pointer dereference

[Dima Stepanov <dimastep@yandex-team.ru>]

Gentle ping. CCing Paolo Bonzini.

Regards, Dima.

On Tue, Jun 19, 2018 at 05:12:16PM +0300, Dima Stepanov wrote:
> Ping.
> 
> Regards, Dima.
> 
> On Wed, Jun 13, 2018 at 11:19:55AM +0300, Dima Stepanov wrote:
> > In the memory_region_do_invalidate_mmio_ptr() routine the section
> > variable is intialized by the memory_region_find() call. The section.mr
> > field can be set to NULL.
> > 
> > Add the check for NULL before trying to drop a section.
> > 
> > Signed-off-by: Dima Stepanov <dimastep@yandex-team.ru>
> > ---
> >  memory.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/memory.c b/memory.c
> > index 3212acc..bb45248 100644
> > --- a/memory.c
> > +++ b/memory.c
> > @@ -2712,7 +2712,7 @@ static void memory_region_do_invalidate_mmio_ptr(CPUState *cpu,
> >      /* Reset dirty so this doesn't happen later. */
> >      cpu_physical_memory_test_and_clear_dirty(offset, size, 1);
> >  
> > -    if (section.mr != mr) {
> > +    if (section.mr && (section.mr != mr)) {
> >          /* memory_region_find add a ref on section.mr */
> >          memory_region_unref(section.mr);
> >          if (MMIO_INTERFACE(section.mr->owner)) {
> > -- 
> > 2.7.4
> > 
> >