Re: [PATCH] qom: fix objects with improper parent type

[Marc-André Lureau]

On Wed, Sep 30, 2020 at 3:47 AM Sergey Nizovtsev <snizovtsev@gmail.com> wrote:
>
> Some objects accidentally inherit ObjectClass instead of Object.
> They compile silently but may crash after downcasting.
>
> In this patch, we introduce a coccinelle script to find broken
> declarations and fix them manually with proper base type.
>
> Signed-off-by: Sergey Nizovtsev <snizovtsev@gmail.com>

thanks!!
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

> ---
>  scripts/coccinelle/qobject-parent-type.cocci | 26 ++++++++++++++++++++
>  include/hw/acpi/vmgenid.h                    |  2 +-
>  include/hw/misc/vmcoreinfo.h                 |  2 +-
>  include/net/can_host.h                       |  2 +-
>  MAINTAINERS                                  |  1 +
>  5 files changed, 30 insertions(+), 3 deletions(-)
>  create mode 100644 scripts/coccinelle/qobject-parent-type.cocci
>
> diff --git a/scripts/coccinelle/qobject-parent-type.cocci
> b/scripts/coccinelle/qobject-parent-type.cocci
> new file mode 100644
> index 0000000000..9afb3edd97
> --- /dev/null
> +++ b/scripts/coccinelle/qobject-parent-type.cocci
> @@ -0,0 +1,26 @@
> +// Highlight object declarations that don't look like object class but
> +// accidentally inherit from it.
> +
> +@match@
> +identifier obj_t, fld;
> +type parent_t =~ ".*Class$";
> +@@
> +struct obj_t {
> +    parent_t fld;
> +    ...
> +};
> +
> +@script:python filter depends on match@
> +obj_t << match.obj_t;
> +@@
> +is_class_obj = obj_t.endswith('Class')
> +cocci.include_match(not is_class_obj)
> +
> +@replacement depends on filter@
> +identifier match.obj_t, match.fld;
> +type match.parent_t;
> +@@
> +struct obj_t {
> +*   parent_t fld;
> +    ...
> +};
> diff --git a/include/hw/acpi/vmgenid.h b/include/hw/acpi/vmgenid.h
> index d50fbacb8e..cb4ad37fc5 100644
> --- a/include/hw/acpi/vmgenid.h
> +++ b/include/hw/acpi/vmgenid.h
> @@ -19,7 +19,7 @@
>  OBJECT_DECLARE_SIMPLE_TYPE(VmGenIdState, VMGENID)
>
>  struct VmGenIdState {
> -    DeviceClass parent_obj;
> +    DeviceState parent_obj;
>      QemuUUID guid;                /* The 128-bit GUID seen by the guest */
>      uint8_t vmgenid_addr_le[8];   /* Address of the GUID (little-endian) */
>  };
> diff --git a/include/hw/misc/vmcoreinfo.h b/include/hw/misc/vmcoreinfo.h
> index ebada6617a..0b7b55d400 100644
> --- a/include/hw/misc/vmcoreinfo.h
> +++ b/include/hw/misc/vmcoreinfo.h
> @@ -24,7 +24,7 @@ DECLARE_INSTANCE_CHECKER(VMCoreInfoState, VMCOREINFO,
>  typedef struct fw_cfg_vmcoreinfo FWCfgVMCoreInfo;
>
>  struct VMCoreInfoState {
> -    DeviceClass parent_obj;
> +    DeviceState parent_obj;
>
>      bool has_vmcoreinfo;
>      FWCfgVMCoreInfo vmcoreinfo;
> diff --git a/include/net/can_host.h b/include/net/can_host.h
> index 4e3ce3f954..caab71bdda 100644
> --- a/include/net/can_host.h
> +++ b/include/net/can_host.h
> @@ -35,7 +35,7 @@
>  OBJECT_DECLARE_TYPE(CanHostState, CanHostClass, CAN_HOST)
>
>  struct CanHostState {
> -    ObjectClass oc;
> +    Object oc;
>
>      CanBusState *bus;
>      CanBusClientState bus_client;
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 5eed1e692b..2160b8196a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2402,6 +2402,7 @@ F: qobject/
>  F: include/qapi/qmp/
>  X: include/qapi/qmp/dispatch.h
>  F: scripts/coccinelle/qobject.cocci
> +F: scripts/coccinelle/qobject-parent-type.cocci
>  F: tests/check-qdict.c
>  F: tests/check-qjson.c
>  F: tests/check-qlist.c
> --
> 2.28.0
>