Re: [PATCH] e1000: ethtool: check on netif_running() before calling e1000_up()

[Alexander Duyck]

On Wed, Jul 18, 2018 at 12:18 PM, Bo Chen <chenbo@xxxxxxx> wrote:
> When the device is not up, the call to 'e1000_up()' from the error handling path
> of 'e1000_set_ringparam()' causes a kernel oops with a null-pointer
> dereference. The null-pointer dereference is triggered in function
> 'e1000_alloc_rx_buffers()' at line 'buffer_info = &rx_ring->buffer_info[i]'.
>
> This bug was reported by COD, a tool for testing kernel module binaries I am
> building. This bug was also detected by KFI from Dr. Kai Cong.
>
> This patch fixes the bug by checking on 'netif_running()' before calling
> 'e1000_up()' in 'e1000_set_ringparam()'.
>
> Signed-off-by: Bo Chen <chenbo@xxxxxxx>

The change below looks good to me.

Acked-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>

> ---
>  drivers/net/ethernet/intel/e1000/e1000_ethtool.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> index bdb3f8e65ed4..c1e4e94f100f 100644
> --- a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> +++ b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> @@ -644,7 +644,8 @@ static int e1000_set_ringparam(struct net_device *netdev,
>  err_alloc_rx:
>         kfree(txdr);
>  err_alloc_tx:
> -       e1000_up(adapter);
> +       if (netif_running(adapter->netdev))
> +               e1000_up(adapter);
>  err_setup:
>         clear_bit(__E1000_RESETTING, &adapter->flags);
>         return err;
> --
> 2.17.0
>