Subject: Re: [PATCH 10/11] IB/mlx5: Fix undefined behavior due to shift overflowing the constant

From: Leon Romanovsky <[email-masked]>
Date: Tue, 5 Apr 2022 21:31:16 +0300

On Tue, Apr 05, 2022 at 05:15:16PM +0200, Borislav Petkov wrote:
> From: Borislav Petkov <[email-masked]>
> 
> Fix:
> 
>   drivers/infiniband/hw/mlx5/main.c: In function ‘translate_eth_legacy_proto_oper’:
>   drivers/infiniband/hw/mlx5/main.c:370:2: error: case label does not reduce to an integer constant
>     case MLX5E_PROT_MASK(MLX5E_50GBASE_KR2):
>     ^~~~
> 
> See https://lore.kernel.org/r/[email-masked] for the gory
> details as to why it triggers with older gccs only.
> 
> Signed-off-by: Borislav Petkov <[email-masked]>
> Cc: Leon Romanovsky <[email-masked]>
> Cc: Saeed Mahameed <[email-masked]>
> Cc: [email-masked]
> Cc: [email-masked]
> ---
>  include/linux/mlx5/port.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

I would like to take this patch to mlx5-next, but it didn't show
nor in patchworks [1] nor in lore [2].

Thanks

[1] https://patchwork.kernel.org/project/linux-rdma/list/
[2] https://lore.kernel.org/linux-rdma/

> 
> diff --git a/include/linux/mlx5/port.h b/include/linux/mlx5/port.h
> index 28a928b0684b..e96ee1e348cb 100644
> --- a/include/linux/mlx5/port.h
> +++ b/include/linux/mlx5/port.h
> @@ -141,7 +141,7 @@ enum mlx5_ptys_width {
>  	MLX5_PTYS_WIDTH_12X	= 1 << 4,
>  };
>  
> -#define MLX5E_PROT_MASK(link_mode) (1 << link_mode)
> +#define MLX5E_PROT_MASK(link_mode) (1U << link_mode)
>  #define MLX5_GET_ETH_PROTO(reg, out, ext, field)	\
>  	(ext ? MLX5_GET(reg, out, ext_##field) :	\
>  	MLX5_GET(reg, out, field))
> -- 
> 2.35.1
>