Subject: Re: [PATCH net-next] net/mlx5: Fix use of uninitialized variable in bridge.c

From: Leon Romanovsky <[email-masked]>
Date: Tue, 14 Sep 2021 15:41:23 +0300

On Tue, Sep 14, 2021 at 03:12:47PM +0300, Leon Romanovsky wrote:
> From: Leon Romanovsky <[email-masked]>
> 
> Rewrite the code to fix the following compilation warnings that were
> discovered once Linus enabled -Werror flag.
> 
> drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:157:11: error:
> variable 'err' is used uninitialized whenever 'if' condition is false
> [-Werror,-Wsometimes-uninitialized]
>         else if (mlx5_esw_bridge_dev_same_hw(rep, esw))
>                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:164:9: note:
> uninitialized use occurs here
>         return err;
>                ^~~
> drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:157:7: note:
> remove the 'if' if its condition is always true
>         else if (mlx5_esw_bridge_dev_same_hw(rep, esw))
>              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:140:9: note:
> initialize the variable 'err' to silence this warning
>         int err;
>                ^
>                 = 0
> drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:262:7: error:
> variable 'err' is used uninitialized whenever switch case is taken
> [-Werror,-Wsometimes-uninitialized]
>         case SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS:
>              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:276:9: note:
> uninitialized use occurs here
>         return err;
>                ^~~
> drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:257:7: error:
> variable 'err' is used uninitialized whenever 'if' condition is false
> [-Werror,-Wsometimes-uninitialized]
>                 if (attr->u.brport_flags.mask & ~(BR_LEARNING |
> BR_FLOOD | BR_MCAST_FLOOD)) {
> 
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:276:9: note:
> uninitialized use occurs here
>         return err;
>                ^~~
> drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:257:3: note:
> remove the 'if' if its condition is always true
>                 if (attr->u.brport_flags.mask & ~(BR_LEARNING |
> BR_FLOOD | BR_MCAST_FLOOD)) {
> 
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:247:9: note:
> initialize the variable 'err' to silence this warning
>         int err;
>                ^
>                 = 0
> 3 errors generated.
> 
> Fixes: ff9b7521468b ("net/mlx5: Bridge, support LAG")
> Reported-by: Naresh Kamboju <[email-masked]>
> Signed-off-by: Leon Romanovsky <[email-masked]>
> ---
>  .../mellanox/mlx5/core/en/rep/bridge.c        | 36 +++++++++++--------
>  1 file changed, 22 insertions(+), 14 deletions(-)

Vlad pointed to me that similar patch was already accepted.
https://patchwork.kernel.org/project/netdevbpf/patch/[email-masked]/

Can we please expedite the fix to Linus so our other branches (RDMA e.t.c)
that are based on pure -rcX from Linus will be compilation error free? 

Thanks