Re: [Qemu-devel] [PATCH v2 1/1] qom/object: Don't poll cast cache for NULL objects

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Wed, May 22, 2013 at 11:19:16AM +1000, peter.crosthwaite@xilinx.com wrote:
> From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> 
> object_dynamic_cast_assert used to be tolerant of NULL objects and not
> assert. It's clear from the implementation that this is the expected
> behavior.
> 
> The preceding check of the cast cache dereferences obj however causing
> a segfault. Fix by conditionalizing the cast cache logic on obj being
> non-null.
> 
> Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> Reviewed-by: Andreas Färber <afaerber@suse.de>
> Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>


Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>


> ---
> Changed from v1: Fixed 2 commit msg typos (AF review)
> 
>  qom/object.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/qom/object.c b/qom/object.c
> index ec88231..803b94b 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -442,7 +442,7 @@ Object *object_dynamic_cast_assert(Object *obj, const char *typename,
>      int i;
>      Object *inst;
>  
> -    for (i = 0; i < OBJECT_CLASS_CAST_CACHE; i++) {
> +    for (i = 0; obj && i < OBJECT_CLASS_CAST_CACHE; i++) {
>          if (obj->class->cast_cache[i] == typename) {
>              goto out;
>          }
> @@ -458,7 +458,7 @@ Object *object_dynamic_cast_assert(Object *obj, const char *typename,
>  
>      assert(obj == inst);
>  
> -    if (obj == inst) {
> +    if (obj && obj == inst) {
>          for (i = 1; i < OBJECT_CLASS_CAST_CACHE; i++) {
>              obj->class->cast_cache[i - 1] = obj->class->cast_cache[i];
>          }
> -- 
> 1.8.3.rc1.44.gb387c77.dirty
>