On Wed, 1 Mar 2023 at 17:29, Sasha Levin <sashal@xxxxxxxxxx> wrote:
>
> From: Johan Hovold <johan+linaro@xxxxxxxxxx>
>
> [ Upstream commit 0217a40d7ba6e71d7f3422fbe89b436e8ee7ece7 ]
>
> Add the missing sanity check to efivars_register() so that it is no
> longer possible to override an already registered set of efivar ops
> (without first deregistering them).
>
> This can help debug initialisation ordering issues where drivers have so
> far unknowingly been relying on overriding the generic ops.
>
> Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
NAK this is not a bugfix.
> ---
> drivers/firmware/efi/vars.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
> index 0ba9f18312f5b..4ca256bcd6971 100644
> --- a/drivers/firmware/efi/vars.c
> +++ b/drivers/firmware/efi/vars.c
> @@ -66,19 +66,28 @@ int efivars_register(struct efivars *efivars,
> const struct efivar_operations *ops,
> struct kobject *kobject)
> {
> + int rv;
> +
> if (down_interruptible(&efivars_lock))
> return -EINTR;
>
> + if (__efivars) {
> + pr_warn("efivars already registered\n");
> + rv = -EBUSY;
> + goto out;
> + }
> +
> efivars->ops = ops;
> efivars->kobject = kobject;
>
> __efivars = efivars;
>
> pr_info("Registered efivars operations\n");
> -
> + rv = 0;
> +out:
> up(&efivars_lock);
>
> - return 0;
> + return rv;
> }
> EXPORT_SYMBOL_GPL(efivars_register);
>
> --
> 2.39.2
>
