[PATCH] net: ethernet: litex: Fix return type of liteeth_start_xmit

[PATCH] net: ethernet: litex: Fix return type of liteeth_start_xmit

[Nathan Huckleberry]

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>
---
 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

Re: [PATCH] net: ethernet: litex: Fix return type of liteeth_start_xmit

[Nathan Chancellor]

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
> 

Re: [PATCH] net: ethernet: litex: Fix return type of liteeth_start_xmit

[Gabriel L. Somlo]

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
> > 

Re: [PATCH] net: ethernet: litex: Fix return type of liteeth_start_xmit

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 12 Sep 2022 12:53:07 -0700 you 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.
> 
> [...]

Here is the summary with links:
  - net: ethernet: litex: Fix return type of liteeth_start_xmit
    https://git.kernel.org/netdev/net-next/c/40662333dd7c

You are awesome, thank you!
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