On 3/11/24 04:37, Zhao Liu wrote:
> From: Zhao Liu <zhao1....@intel.com>
>
> As the comment in qapi/error, passing @errp to error_prepend() requires
> ERRP_GUARD():
>
> * = Why, when and how to use ERRP_GUARD() =
> *
> * Without ERRP_GUARD(), use of the @errp parameter is restricted:
> ...
> * - It should not be passed to error_prepend(), error_vprepend() or
> * error_append_hint(), because that doesn't work with &error_fatal.
> * ERRP_GUARD() lifts these restrictions.
> *
> * To use ERRP_GUARD(), add it right at the beginning of the function.
> * @errp can then be used without worrying about the argument being
> * NULL or &error_fatal.
>
> ERRP_GUARD() could avoid the case when @errp is &error_fatal, the user
> can't see this additional information, because exit() happens in
> error_setg earlier than information is added [1].
>
> The iommufd_backend_set_fd() passes @errp to error_prepend(), to avoid
> the above issue, add missing ERRP_GUARD() at the beginning of this
> function.
>
> [1]: Issue description in the commit message of commit ae7c80a7bd73
> ("error: New macro ERRP_GUARD()").
>
> Cc: Yi Liu <yi.l....@intel.com>
> Cc: Eric Auger <eric.au...@redhat.com>
> Cc: Zhenzhong Duan <zhenzhong.d...@intel.com>
> Signed-off-by: Zhao Liu <zhao1....@intel.com>
> Reviewed-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
Reviewed-by: Eric Auger <eric.au...@redhat.com>
Eric
> ---
> backends/iommufd.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/backends/iommufd.c b/backends/iommufd.c
> index 1ef683c7b080..62a79fa6b049 100644
> --- a/backends/iommufd.c
> +++ b/backends/iommufd.c
> @@ -43,6 +43,7 @@ static void iommufd_backend_finalize(Object *obj)
>
> static void iommufd_backend_set_fd(Object *obj, const char *str, Error
> **errp)
> {
> + ERRP_GUARD();
> IOMMUFDBackend *be = IOMMUFD_BACKEND(obj);
> int fd = -1;
>
