Re: [PATCH net-next-2.6] net/core: neighbour update Oops

[Eric Dumazet <eric.dumazet@gmail.com>]

Le mardi 13 juillet 2010 à 08:23 -0700, Doug Kehn a écrit :
> When configuring DMVPN (GRE + openNHRP) and a GRE remote
> address is configured a kernel Oops is observed.  The
> obserseved Oops is caused by a NULL header_ops pointer
> (neigh->dev->header_ops) in neigh_update_hhs() when
> 
> void (*update)(struct hh_cache*, const struct net_device*, const unsigned char *)
> = neigh->dev->header_ops->cache_update;
> 
> is executed.  The dev associated with the NULL header_ops is
> the GRE interface.  This patch guards against the
> possibility that header_ops is NULL.
> 
> This Oops was first observed in kernel version 2.6.26.8.
> 
> Signed-off-by: Doug Kehn <rdkehn@yahoo.com>

Acked-by: Eric Dumazet <eric.dumazet@gmail.com>

> ---
>  net/core/neighbour.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/net/core/neighbour.c b/net/core/neighbour.c
> index 6ba1c0e..a4e0a74 100644
> --- a/net/core/neighbour.c
> +++ b/net/core/neighbour.c
> @@ -949,7 +949,10 @@ static void neigh_update_hhs(struct neighbour *neigh)
>  {
>  	struct hh_cache *hh;
>  	void (*update)(struct hh_cache*, const struct net_device*, const unsigned char *)
> -		= neigh->dev->header_ops->cache_update;
> +		= NULL;
> +
> +	if (neigh->dev->header_ops)
> +		update = neigh->dev->header_ops->cache_update;
>  
>  	if (update) {
>  		for (hh = neigh->hh; hh; hh = hh->hh_next) {