[Intel-wired-lan] [PATCH][-next] ixgbe: don't clear_bit on xdp_ring->state if xdp_ring is null

[Bowers, AndrewX]

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces at osuosl.org] On
> Behalf Of Colin King
> Sent: Thursday, October 4, 2018 10:58 AM
> To: Kirsher, Jeffrey T <jeffrey.t.kirsher at intel.com>; David S . Miller
> <davem at davemloft.net>; intel-wired-lan at lists.osuosl.org;
> netdev at vger.kernel.org
> Cc: kernel-janitors at vger.kernel.org
> Subject: [Intel-wired-lan] [PATCH][-next] ixgbe: don't clear_bit on xdp_ring-
> >state if xdp_ring is null
> 
> From: Colin Ian King <colin.king at canonical.com>
> 
> There is an earlier check to see if xdp_ring is null when configuring the tx ring,
> so assuming that it can still be null, the clearing of the xdp_ring->state
> currently could end up with a null pointer dereference.  Fix this by only
> clearing the bit if xdp_ring is not null.
> 
> Detected by CoverityScan, CID#1473795 ("Dereference after null check")
> 
> Fixes: 024aa5800f32 ("ixgbe: added Rx/Tx ring disable/enable functions")
> Signed-off-by: Colin Ian King <colin.king at canonical.com>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Tested-by: Andrew Bowers <andrewx.bowers at intel.com>