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Piccoli" , "Tony Luck" , "Kees Cook" , "Ilias Apalodimas" Message-Id: <4068dc87-df3b-4c08-b4e7-ee8746861d52@app.fastmail.com> In-Reply-To: <04e11e34-1b3f-4892-adc5-ae2ea040c004@tti0.net> References: <20260625171214.8058-1-theodore@tti0.net> <6ecd6385-37c6-4ae8-8413-53a6e8602635@app.fastmail.com> <55870f62-ee17-4aed-850e-790517f68eee@app.fastmail.com> <04e11e34-1b3f-4892-adc5-ae2ea040c004@tti0.net> Subject: Re: [PATCH] efi: Make EFI_VARS_PSTORE depend on EFIVAR_FS Content-Type: text/plain Content-Transfer-Encoding: 7bit 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.