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From: Ard Biesheuvel <ardb@kernel.org>
Date: Sat, 23 Mar 2024 14:15:50 +0200
Message-ID: <CAMj1kXF0oM4CZM6GBQ+JNdk0ipf62cVJWjaR7Qy8YEU2B6=MVg@mail.gmail.com>
Subject: Re: [PATCH v2] efi: fix panic in kdump kernel
To: Oleksandr Tymoshenko <ovt@google.com>
Cc: Johan Hovold <johan+linaro@kernel.org>, stable@vger.kernel.org, 
	linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org
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On Sat, 23 Mar 2024 at 08:33, Oleksandr Tymoshenko <ovt@google.com> wrote:
>
> Check if get_next_variable() is actually valid pointer before
> calling it. In kdump kernel this method is set to NULL that causes
> panic during the kexec-ed kernel boot.
>
> Tested with QEMU and OVMF firmware.
>
> Fixes: bad267f9e18f ("efi: verify that variable services are supported")
> Cc: stable@vger.kernel.org
> Signed-off-by: Oleksandr Tymoshenko <ovt@google.com>

Thanks. Queued as a fix.

> ---
> Changes in v2:
>   - Style fix
>   - Added Cc: stable
>   - Added Fixes: trailer
> ---
>  drivers/firmware/efi/efi.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 8859fb0b006d..fdf07dd6f459 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -203,6 +203,8 @@ static bool generic_ops_supported(void)
>
>         name_size = sizeof(name);
>
> +       if (!efi.get_next_variable)
> +               return false;
>         status = efi.get_next_variable(&name_size, &name, &guid);
>         if (status == EFI_UNSUPPORTED)
>                 return false;
> --
> 2.44.0.396.g6e790dbe36-goog
>