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SubjectRe: [PATCH] efi/apple-properties: Replace zero-length array with flexible-array member
On Wed, 12 Feb 2020 at 00:11, Gustavo A. R. Silva
<gustavo@embeddedor.com> wrote:
>
> The current codebase makes use of the zero-length array language
> extension to the C90 standard, but the preferred mechanism to declare
> variable-length types such as these ones is a flexible array member[1][2],
> introduced in C99:
>
> struct foo {
> int stuff;
> struct boo array[];
> };
>
> By making use of the mechanism above, we will get a compiler warning
> in case the flexible array does not occur last in the structure, which
> will help us prevent some kind of undefined behavior bugs from being
> inadvertenly introduced[3] to the codebase from now on.
>
> This issue was found with the help of Coccinelle.
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
> [2] https://github.com/KSPP/linux/issues/21
> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Queued in efi/next

Thanks,

> ---
> drivers/firmware/efi/apple-properties.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/efi/apple-properties.c b/drivers/firmware/efi/apple-properties.c
> index 0e206c9e0d7a..590c9003f3b4 100644
> --- a/drivers/firmware/efi/apple-properties.c
> +++ b/drivers/firmware/efi/apple-properties.c
> @@ -31,7 +31,7 @@ __setup("dump_apple_properties", dump_properties_enable);
> struct dev_header {
> u32 len;
> u32 prop_count;
> - struct efi_dev_path path[0];
> + struct efi_dev_path path[];
> /*
> * followed by key/value pairs, each key and value preceded by u32 len,
> * len includes itself, value may be empty (in which case its len is 4)
> @@ -42,7 +42,7 @@ struct properties_header {
> u32 len;
> u32 version;
> u32 dev_count;
> - struct dev_header dev_header[0];
> + struct dev_header dev_header[];
> };
>
> static void __init unmarshal_key_value_pairs(struct dev_header *dev_header,
> --
> 2.25.0
>

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