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Date:   Tue, 13 Sep 2022 15:29:15 -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>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: davicom: Fix return type of dm9000_start_xmit
Message-ID: <YyEEO0ttQhMvLFIC@dev-arch.thelio-3990X>
References: <20220912194722.809525-1-nhuck@google.com>
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On Mon, Sep 12, 2022 at 12:47:19PM -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 dm9000_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/davicom/dm9000.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/davicom/dm9000.c b/drivers/net/ethernet/davicom/dm9000.c
> index 0985ab216566..186a5e0a7862 100644
> --- a/drivers/net/ethernet/davicom/dm9000.c
> +++ b/drivers/net/ethernet/davicom/dm9000.c
> @@ -1012,7 +1012,7 @@ static void dm9000_send_packet(struct net_device *dev,
>   *  Hardware start transmission.
>   *  Send a packet to media from the upper layer.
>   */
> -static int
> +static netdev_tx_t
>  dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev)
>  {
>  	unsigned long flags;
> -- 
> 2.37.2.789.g6183377224-goog
>