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Message-ID: <CAKgT0UceBCgtae2NMpu236fYvJOU+0uzQDk5c6rgRXqB+7CcMQ@mail.gmail.com>
Date: Wed, 18 Jul 2018 13:49:40 -0700
From: Alexander Duyck <alexander.duyck@...il.com>
To: Bo Chen <chenbo@....edu>
Cc: Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
David Miller <davem@...emloft.net>,
Netdev <netdev@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>, phenix1108@...il.com,
intel-wired-lan <intel-wired-lan@...ts.osuosl.org>
Subject: Re: [PATCH] e1000: ethtool: check on netif_running() before calling e1000_up()
On Wed, Jul 18, 2018 at 12:18 PM, Bo Chen <chenbo@....edu> 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@....edu>
The change below looks good to me.
Acked-by: Alexander Duyck <alexander.h.duyck@...el.com>
> ---
> 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
>
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