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Date:   Tue, 13 Sep 2022 15:31:11 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Nathan Huckleberry <nhuck@google.com>
Cc:     Dan Carpenter <error27@gmail.com>, llvm@lists.linux.dev,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Karol Gugala <kgugala@antmicro.com>,
        Mateusz Holenko <mholenko@antmicro.com>,
        Gabriel Somlo <gsomlo@gmail.com>,
        Joel Stanley <joel@jms.id.au>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: ethernet: litex: Fix return type of
 liteeth_start_xmit
Message-ID: <YyEErzoi9+8NMRCP@dev-arch.thelio-3990X>
References: <20220912195307.812229-1-nhuck@google.com>
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On Mon, Sep 12, 2022 at 12:53:07PM -0700, Nathan Huckleberry wrote:
> The ndo_start_xmit field in net_device_ops is expected to be of type
> netdev_tx_t (*ndo_start_xmit)(struct sk_buff *skb, struct net_device *dev).
> 
> The mismatched return type breaks forward edge kCFI since the underlying
> function definition does not match the function hook definition.
> 
> The return type of liteeth_start_xmit should be changed from int to
> netdev_tx_t.
> 
> Reported-by: Dan Carpenter <error27@gmail.com>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1703
> Cc: llvm@lists.linux.dev
> Signed-off-by: Nathan Huckleberry <nhuck@google.com>

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
>  drivers/net/ethernet/litex/litex_liteeth.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/litex/litex_liteeth.c b/drivers/net/ethernet/litex/litex_liteeth.c
> index fdd99f0de424..35f24e0f0934 100644
> --- a/drivers/net/ethernet/litex/litex_liteeth.c
> +++ b/drivers/net/ethernet/litex/litex_liteeth.c
> @@ -152,7 +152,8 @@ static int liteeth_stop(struct net_device *netdev)
>  	return 0;
>  }
>  
> -static int liteeth_start_xmit(struct sk_buff *skb, struct net_device *netdev)
> +static netdev_tx_t liteeth_start_xmit(struct sk_buff *skb,
> +				      struct net_device *netdev)
>  {
>  	struct liteeth *priv = netdev_priv(netdev);
>  	void __iomem *txbuffer;
> -- 
> 2.37.2.789.g6183377224-goog
>