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

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

[Arnd Bergmann]

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 <arnd@arndb.de>
---
 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

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

[Tariq Toukan]

On 7/10/2019 4:06 PM, 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 <arnd@arndb.de>
> ---
>   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);
> 

Reviewed-by: Tariq Toukan <tariqt@mellanox.com>

Thanks!

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

[Nathan Chancellor]

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 <arnd@arndb.de>
> ---
>  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