efi: efivars: prevent double registration

From: Johan Hovold <johan+linaro@kernel.org>

[ Commit 0217a40d7b upstream ]

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@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ard Biesheuvel 2024-03-04 12:19:40 +01:00 committed by Greg Kroah-Hartman
parent e58f2862e9
commit 33d064aecd

View file

@ -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);