2019-07-10 13:27:53

by Arnd Bergmann

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

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 protected]>
---
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

2019-07-10 14:23:30

by Tariq Toukan

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

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 <[email protected]>
> ---
> 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 <[email protected]>

Thanks!

2019-07-10 17:16:08

by Nathan Chancellor

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

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 protected]>
> ---
> 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