On Tue, Feb 11, 2020 at 05:24:20PM -0600, 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.
Same here, the scripts may need to be updated as you missed a couple of
instances:
$ git grep '\[0\];' drivers/usb/serial
...
drivers/usb/serial/io_usbvend.h: __u8 Data[0]; // Data starts here
drivers/usb/serial/io_usbvend.h: __u8 Data[0]; // Download starts here
...
Could you replace these as well so that is done in one patch per
subsystem?
> [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@xxxxxxxxxxxxxx>
> ---
> drivers/usb/serial/ti_usb_3410_5052.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
> index dd0ad67aa71e..db3ab25d9228 100644
> --- a/drivers/usb/serial/ti_usb_3410_5052.c
> +++ b/drivers/usb/serial/ti_usb_3410_5052.c
> @@ -219,7 +219,7 @@ struct ti_write_data_bytes {
> u8 bDataCounter;
> __be16 wBaseAddrHi;
> __be16 wBaseAddrLo;
> - u8 bData[0];
> + u8 bData[];
> } __packed;
>
> struct ti_read_data_request {
> @@ -234,7 +234,7 @@ struct ti_read_data_bytes {
> __u8 bCmdCode;
> __u8 bModuleId;
> __u8 bErrorCode;
> - __u8 bData[0];
> + __u8 bData[];
> } __packed;
>
> /* Interrupt struct */
Thanks,
Johan
