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Date:   Tue, 13 Sep 2022 15:30:20 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Nathan Huckleberry <nhuck@google.com>
Cc:     Dan Carpenter <error27@gmail.com>, llvm@lists.linux.dev,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
        Maxim Kiselev <bigunclemax@gmail.com>,
        Minghao Chi <chi.minghao@zte.com.cn>,
        linux-omap@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: ethernet: ti: davinci_emac: Fix return type of
 emac_dev_xmit
Message-ID: <YyEEfEHlY5zMjWHg@dev-arch.thelio-3990X>
References: <20220912195023.810319-1-nhuck@google.com>
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On Mon, Sep 12, 2022 at 12:50:19PM -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 emac_dev_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/ti/davinci_emac.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/ti/davinci_emac.c b/drivers/net/ethernet/ti/davinci_emac.c
> index 2a3e4e842fa5..e203a5984f03 100644
> --- a/drivers/net/ethernet/ti/davinci_emac.c
> +++ b/drivers/net/ethernet/ti/davinci_emac.c
> @@ -949,7 +949,7 @@ static void emac_tx_handler(void *token, int len, int status)
>   *
>   * Returns success(NETDEV_TX_OK) or error code (typically out of desc's)
>   */
> -static int emac_dev_xmit(struct sk_buff *skb, struct net_device *ndev)
> +static netdev_tx_t emac_dev_xmit(struct sk_buff *skb, struct net_device *ndev)
>  {
>  	struct device *emac_dev = &ndev->dev;
>  	int ret_code;
> -- 
> 2.37.2.789.g6183377224-goog
>