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Date:   Wed, 14 Sep 2022 08:06:56 -0400
From:   "Gabriel L. Somlo" <gsomlo@gmail.com>
To:     Nathan Chancellor <nathan@kernel.org>
Cc:     Nathan Huckleberry <nhuck@google.com>,
        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>,
        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: <YyHD4MX0Pvckb6XW@errol.ini.cmu.edu>
References: <20220912195307.812229-1-nhuck@google.com>
 <YyEErzoi9+8NMRCP@dev-arch.thelio-3990X>
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In-Reply-To: <YyEErzoi9+8NMRCP@dev-arch.thelio-3990X>
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On Tue, Sep 13, 2022 at 03:31:11PM -0700, Nathan Chancellor wrote:
> 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>

Acked-by: Gabriel Somlo <gsomlo@gmail.com>

Thanks,
--G

 
> > ---
> >  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
> >