From: Johan Hovold johan+linaro@kernel.org
[ 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@kernel.org Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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);