[PATCH] efi: Suppress spurious "Couldn't get size" error

The current efi code emits the error message like
   Couldn't get size: 0x800000000000000e
on various Dell and other machines.  Although the whole problem is the
buggy firmware, showing this as an error level is rather annoying, as
the error message appears over the boot splash.  Basically this is the
result of missing entry and we have no explicit way to fix it for such
a firmware problem, the error message may be suppressed.

This patch changes the error print condition and suppresses the error
message if status is EFI_NOT_FOUND.  It's a partial patch from the
more comprehensive one Joey Lee submitted in the past.

Link: https://lore.kernel.org/linux-efi/20190322103350.27764-2-jlee@suse.com/
Cc: Joey Lee <jlee@suse.com>
Signed-off-by: Takashi Iwai <redacted>
---
 security/integrity/platform_certs/load_uefi.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
index 111898aad56e..8501ea62cb3e 100644
--- a/security/integrity/platform_certs/load_uefi.c
+++ b/security/integrity/platform_certs/load_uefi.c

@@ -44,7 +44,8 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
 
 	status = efi.get_variable(name, guid, NULL, &lsize, &tmpdb);
 	if (status != EFI_BUFFER_TOO_SMALL) {
-		pr_err("Couldn't get size: 0x%lx\n", status);
+		if (status != EFI_NOT_FOUND)
+			pr_err("Couldn't get size: 0x%lx\n", status);
 		return NULL;
 	}
 

-- 
2.16.4

On Mon, 17 Feb 2020 at 16:45, Takashi Iwai [off-list ref] wrote:

The current efi code emits the error message like
   Couldn't get size: 0x800000000000000e
on various Dell and other machines.  Although the whole problem is the
buggy firmware, showing this as an error level is rather annoying, as
the error message appears over the boot splash.  Basically this is the
result of missing entry and we have no explicit way to fix it for such
a firmware problem, the error message may be suppressed.

This patch changes the error print condition and suppresses the error
message if status is EFI_NOT_FOUND.  It's a partial patch from the
more comprehensive one Joey Lee submitted in the past.

Link: https://lore.kernel.org/linux-efi/20190322103350.27764-2-jlee@suse.com/
Cc: Joey Lee <jlee@suse.com>
Signed-off-by: Takashi Iwai <redacted>

Hello Takashi,

Javier sent a more comprehensive fix for this today. The problem is
not buggy firmware, but buggy kernel :-)
(the code assumes that all systems boot via shim, and that certain EFI
variables are therefore guaranteed to exist, which is not the case)

https://lore.kernel.org/linux-efi/CAKv+Gu-a5Bo9i=K55pa3jEXRq-u5JYVGp1jFEE=UY5B=6eUkRQ@mail.gmail.com

-- 
Ard.

On Mon, 17 Feb 2020 17:06:57 +0100,
Ard Biesheuvel wrote:

On Mon, 17 Feb 2020 at 16:45, Takashi Iwai [off-list ref] wrote:

quoted

The current efi code emits the error message like
   Couldn't get size: 0x800000000000000e
on various Dell and other machines.  Although the whole problem is the
buggy firmware, showing this as an error level is rather annoying, as
the error message appears over the boot splash.  Basically this is the
result of missing entry and we have no explicit way to fix it for such
a firmware problem, the error message may be suppressed.

This patch changes the error print condition and suppresses the error
message if status is EFI_NOT_FOUND.  It's a partial patch from the
more comprehensive one Joey Lee submitted in the past.

Link: https://lore.kernel.org/linux-efi/20190322103350.27764-2-jlee@suse.com/
Cc: Joey Lee <jlee@suse.com>
Signed-off-by: Takashi Iwai <redacted>

Hello Takashi,

Javier sent a more comprehensive fix for this today. The problem is
not buggy firmware, but buggy kernel :-)
(the code assumes that all systems boot via shim, and that certain EFI
variables are therefore guaranteed to exist, which is not the case)

https://lore.kernel.org/linux-efi/CAKv+Gu-a5Bo9i=K55pa3jEXRq-u5JYVGp1jFEE=UY5B=6eUkRQ@mail.gmail.com

Awesome, then please scratch mine.
Thanks!


Takashi