net/core: neighbour update Oops

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Doug Kehn 2010-07-14 18:02:16 -07:00 committed by David S. Miller
parent 87fd308cfc
commit 91a72a7059
1 changed files with 4 additions and 1 deletions

View File

@ -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) {