From 0217a40d7ba6e71d7f3422fbe89b436e8ee7ece7 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 19 Jan 2023 17:42:55 +0100 Subject: [PATCH] efi: efivars: prevent double registration 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 Signed-off-by: Ard Biesheuvel --- 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 f34e7741e0c36..bd75b87f5fc16 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -62,18 +62,27 @@ EXPORT_SYMBOL_GPL(efivar_is_available); int efivars_register(struct efivars *efivars, const struct efivar_operations *ops) { + 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 = efivars; pr_info("Registered efivars operations\n"); - + rv = 0; +out: up(&efivars_lock); - return 0; + return rv; } EXPORT_SYMBOL_GPL(efivars_register); -- 2.30.2