Re: [PATCH] efi: Make EFI_VARS_PSTORE depend on EFIVAR_FS

["Ard Biesheuvel" <ardb@kernel.org>]

On Thu, 20 Aug 2026, at 20:54, Theodore Tucker wrote:
> Hi,
>
> On 20/08/2026 12:49, Ard Biesheuvel wrote:
>> 
>> Actually, EFI pstore does not depend on efivarfs, it only depends on
>> the efivars layer.
>> 
>> Why do you think it needs to depend on EFIVAR_FS?
>
> When building a 7.0 kernel for x86 with `make alldefconfig` and then 
> enabling CONFIG_EFI, CONFIG_PSTORE, and CONFIG_EFI_VARS_PSTORE, I found 
> that the EFI pstore backend failed to register 
> (/sys/module/pstore/parameters/backend was empty after boot) unless 
> CONFIG_EFIVAR_FS had also been enabled explicitly.
>
> I can see now that EFI pstore code should not need the efivarfs, and 
> neither should userspace, since it gets access to any logs through 
> /sys/fs/pstore. So I do appreciate that my patch may not be the right 
> fix here, and I proposed it not as an expert on the internals of EFI 
> pstore, but from experimentation as a user. Sorry for the noise.
>

No worries.

> I eventually ended up using the ramoops pstore backend so unfortunately 
> no longer have the exact kernel configurations I used when this tripped 
> me up.
>
> Thanks and kind regards,
>

Thanks for the context. I've dropped your patch from the queue.

It would be nice to understand what exactly went wrong in your case,
but I agree it is probably not worth your time (or mine) to try and
reproduce the exact conditions under which it occurred.

-- 
Ard.