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Date:   Tue, 14 Sep 2021 15:41:23 +0300
From:   Leon Romanovsky <leonro@nvidia.com>
To:     "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Saeed Mahameed <saeedm@nvidia.com>
CC:     <linux-kernel@vger.kernel.org>, <linux-rdma@vger.kernel.org>,
        Mark Bloch <mbloch@nvidia.com>,
        Naresh Kamboju <naresh.kamboju@linaro.org>,
        <netdev@vger.kernel.org>, Roi Dayan <roid@nvidia.com>,
        Vlad Buslov <vladbu@nvidia.com>
Subject: Re: [PATCH net-next] net/mlx5: Fix use of uninitialized variable in
 bridge.c
Message-ID: <YUCYc7XkOVWS8h1F@unreal>
References: <9e9eb5df93dbcba6faff199d71222785c1f1faf7.1631621485.git.leonro@nvidia.com>
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On Tue, Sep 14, 2021 at 03:12:47PM +0300, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
> 
> 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 <naresh.kamboju@linaro.org>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  .../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/20210907212420.28529-2-saeed@kernel.org/

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