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From:   Ard Biesheuvel <ardb@kernel.org>
To:     sbinding@opensource.cirrus.com
Cc:     andriy.shevchenko@intel.com, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org, patches@opensource.cirrus.com,
        rafael@kernel.org, sakari.ailus@linux.intel.com,
        Ard Biesheuvel <ardb@kernel.org>
Subject: Re: [PATCH v1] ACPI: Property: Fix type detection of unified integer reading functions
Date:   Thu, 25 Aug 2022 09:25:05 +0200
Message-Id: <20220825072505.316002-1-ardb@kernel.org>
In-Reply-To: <20220812130645.14710-1-sbinding@opensource.cirrus.com>
References: <20220812130645.14710-1-sbinding@opensource.cirrus.com>
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> The current code expects the type of the value to be an integer type,
> instead the value passed to the macro is a pointer.
> Ensure the size comparison uses the correct pointer type to choose the
> max value, instead of using the integer type.
> 
> Fixes: 923044133367 ("ACPI: property: Unify integer value reading functions")
> 
> Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

Can we get this queued up and sent out please? This is breaking some ACPI arm64
systems, which use device properties for their MAC addresses.

Some grumbling about the original patch below.

> ---
>  drivers/acpi/property.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> index 7b3ad8ed2f4e..b1d4a8db89df 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -1043,10 +1043,10 @@ static int acpi_data_prop_read_single(const struct acpi_device_data *data,
>  				break;					\
>  			}						\
>  			if (__items[i].integer.value > _Generic(__val,	\
> -								u8: U8_MAX, \
> -								u16: U16_MAX, \
> -								u32: U32_MAX, \
> -								u64: U64_MAX, \
> +								u8 *: U8_MAX, \
> +								u16 *: U16_MAX, \
> +								u32 *: U32_MAX, \
> +								u64 *: U64_MAX, \
>  								default: 0U)) { \

Why is there a default here? Having one is what hides the fact that the patch was completely broken.

>  				ret = -EOVERFLOW;			\
>  				break;					\
> 

Also, I must ask: given how broken the original patch is, I suppose no testing whatsoever was done? 

Thanks,
Ard.