lkml.org 
[lkml]   [2020]   [Feb]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [greybus-dev] [PATCH] staging: greybus: Replace zero-length array with flexible-array member
From
Date
On 2/11/20 3:12 PM, Gustavo A. R. Silva 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>
> ---
> drivers/staging/greybus/raw.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/greybus/raw.c b/drivers/staging/greybus/raw.c
> index 838acbe84ca0..2b301b2aa107 100644
> --- a/drivers/staging/greybus/raw.c
> +++ b/drivers/staging/greybus/raw.c
> @@ -30,7 +30,7 @@ struct gb_raw {
> struct raw_data {
> struct list_head entry;
> u32 len;
> - u8 data[0];
> + u8 data[];
> };
>
> static struct class *raw_class;
>

Does the kamlloc() call in receive_data() have any problems
with the sizeof(*raw_data) passed as its argument?

I'm not entirely sure what sizeof(struct-with-flexible-array-member)
produces.

-Alex

\
 
 \ /
  Last update: 2020-02-11 23:16    [W:0.073 / U:50.304 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site