Subject: Re: [PATCH] [net-next] net/mlx5e: avoid uninitialized variable use

From: Nathan Chancellor <[email-masked]>
Date: Wed, 10 Jul 2019 10:14:13 -0700

On Wed, Jul 10, 2019 at 03:06:25PM +0200, Arnd Bergmann wrote:
> clang points to a variable being used in an unexpected
> code path:
> 
> drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c:251:2: warning: variable 'rec_seq_sz' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized]
>         default:
>         ^~~~~~~
> drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c:255:46: note: uninitialized use occurs here
>         skip_static_post = !memcmp(rec_seq, &rn_be, rec_seq_sz);
>                                                     ^~~~~~~~~~
> 
> From looking at the function logic, it seems that there is no
> sensible way to continue here, so just return early and hope
> for the best.
> 
> Fixes: d2ead1f360e8 ("net/mlx5e: Add kTLS TX HW offload support")
> Signed-off-by: Arnd Bergmann <[email-masked]>
> ---
>  drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c
> index 3f5f4317a22b..5c08891806f0 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c
> @@ -250,6 +250,7 @@ tx_post_resync_params(struct mlx5e_txqsq *sq,
>  	}
>  	default:
>  		WARN_ON(1);
> +		return;
>  	}
>  
>  	skip_static_post = !memcmp(rec_seq, &rn_be, rec_seq_sz);
> -- 
> 2.20.0
> 

Looks like my identical patch got picked up in net-next:

https://git.kernel.org/davem/net-next/c/1ff2f0fa450ea4e4f87793d9ed513098ec6e12be

Good to know the fix was the same.

Cheers,
Nathan