Re: [Qemu-devel] [PATCH 2/2] qom: detect bad reentrance during object_class_foreach

[Peter Crosthwaite]

On Wed, Dec 4, 2013 at 1:42 AM, Paolo Bonzini <address@hidden> wrote:
> From: Hervé Poussineau <address@hidden>
>
> We should not modify the type hash table while it is being iterated on.
> Assert that it does not happen.
>
> Signed-off-by: Hervé Poussineau <address@hidden>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
>  qom/object.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/qom/object.c b/qom/object.c
> index 3a43186..1dee9f0 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -78,8 +78,10 @@ static GHashTable *type_table_get(void)
>      return type_table;
>  }
>
> +static bool enumerating = false;

Global variable could probably use a more descriptive name.

Regards,
Peter

>  static void type_table_add(TypeImpl *ti)
>  {
> +    assert(!enumerating);
>      g_hash_table_insert(type_table_get(), (void *)ti->name, ti);
>  }
>
> @@ -666,7 +668,9 @@ void object_class_foreach(void (*fn)(ObjectClass *klass, 
> void *opaque),
>  {
>      OCFData data = { fn, implements_type, include_abstract, opaque };
>
> +    enumerating = true;
>      g_hash_table_foreach(type_table_get(), object_class_foreach_tramp, 
> &data);
> +    enumerating = false;
>  }
>
>  int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
> --
> 1.8.4.2
>
>