Veaceslav Falico says:
====================
Recent patches revealed an old bug, which was there for quite awhile. It's
related to vlan on top of bonding and ndo_neigh_setup(). When vlan device
is initiated, it calls its real_dev->ndo_neigh_setup(), and in case of
bonding - it will modify neigh_parms->neigh_setup to point to
bond_neigh_init, while neigh_parms are of vlan's dev.
This way, when neigh_parms->neigh_setup() of vlan's dev is called, the
bonding function will be called, which expects the dev to be struct
bonding, but will receive a vlan dev.
It was hidden before because of bond->first_slave usage. Now, with
Nikolay's conversion to list/RCU, first_slave is gone and we hit a null
pointer dereference when working with lists/slave.
First patch moves ndo_neigh_setup() in neigh_parms_alloc() to the bottom,
so that the ->dev will be available to the caller. It doesn't really change
anything, however is needed for the second patch.
Second patch makes bond_neigh_setup() (bond->ndo_neigh_setup()) check if
the neigh_parms are really from a bonding dev, and only modify the
neigh_setup in this case.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>