linux-kernel - Re: [PATCH] x86/efi: Free efi_pgd with free

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Message-ID: <CAKv+Gu8hXOLHLrBMJLYnDyW8xYhSHTAsNk6i034KA7gThjSpJQ@mail.gmail.com>
Date:   Tue, 28 May 2019 15:09:38 +0200
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Lennart Glauer <mail@...nart-glauer.de>
Cc:     Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        linux-efi <linux-efi@...r.kernel.org>,
        platform-driver-x86@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86/efi: Free efi_pgd with free_pages()

Hi Lennart,

Thanks for the patch.

On Tue, 28 May 2019 at 14:58, Lennart Glauer <mail@...nart-glauer.de> wrote:
>
> This patch fixes another occurrence of free_page() that was missed
> in 06ace26.

Please don't trim commit IDs like that. I think 12 digits is our
current minimum?

error: short SHA1 06ace26 is ambiguous
hint: The candidates are:
hint:   06ace26edc14 commit 2016-02-12 - staging: lustre: fix all NULL
comparisons in LNet layer
hint:   06ace26f4e6f commit 2018-03-22 - x86/efi: Free efi_pgd with free_pages()

> The efi_pgd is allocated as PGD_ALLOCATION_ORDER pages and therefore must
> also be freed as PGD_ALLOCATION_ORDER pages with free_pages().
>
> Signed-off-by: Lennart Glauer <mail@...nart-glauer.de>

Acked-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>

Ingo, can you take this directly? I can't really test this anyway.


> ---
>  arch/x86/platform/efi/efi_64.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index 08ce8177c3af..acad22a44774 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -222,7 +222,7 @@ int __init efi_alloc_page_tables(void)
>         pgd = efi_pgd + pgd_index(EFI_VA_END);
>         p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
>         if (!p4d) {
> -               free_page((unsigned long)efi_pgd);
> +               free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
>                 return -ENOMEM;
>         }
>
> --
> 2.17.1