[PATCH] [RFC] lib: efi_loader: don't delete invalid handles

[Simon Glass]

Hi Etienne,

On Wed, 7 Sept 2022 at 02:20, Etienne Carriere
<etienne.carriere at linaro.org> wrote:
>
> Changes efi_delete_handle() to not free EFI handles that are not related
> to EFI objects.
>
> This change tries to resolved an issue seen since U-Boot v2022.07
> in which EFI ExitBootService  attempts to release some EFI handles twice.
>
> The issue was seen booting a EFI shell that invokes 'connect -r' and
> then boots a Linux kernel. Execution of connect command makes EFI
> subsystem to bind a block device for each root block devices EFI handles.
> However these EFI device handles are already bound to a driver and we
> can have 2 registered devices relating to the same EFI handler. On
> ExitBootService, the loop removing the devices makes these EFI handles
> to be released twice which corrupts memory.
>
> This patch prevents the memory release operation caused by the issue but
> I don't think this patch is the right way to addresse the problem. Any
> help will be much appreciated.
>
> Signed-off-by: Etienne Carriere <etienne.carriere at linaro.org>
> ---
>  lib/efi_loader/efi_boottime.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)

+AKASHI Takahiro who has been working on resolving the mismatch
between driver model and the EFI implementation. We should be able to
attach EFI data structures to driver model devices, which may help
with this issue.

What is the next step, there?

Regards,
Simon