Re: [B.A.T.M.A.N.] [PATCH 2/2] batman-adv: Fix reference counting of hardif_neigh_node object for neigh_node

[Marek Lindner <mareklindner@neomailbox.ch>]

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On Friday, March 11, 2016 16:44:06 Sven Eckelmann wrote:
> The batadv_neigh_node was specific to a batadv_hardif_neigh_node and held
> an implicit reference to it. But this reference was never stored in form of
> a pointer in the batadv_neigh_node itself. Instead
> batadv_neigh_node_release depends on a consistent state of
> hard_iface->neigh_list and that batadv_hardif_neigh_get always returns the
> batadv_hardif_neigh_node object which it has a reference for. But
> batadv_hardif_neigh_get cannot guarantee that because it is working only
> with rcu_read_lock on this list. It can therefore happen that a neigh_addr
> is in this list twice or that batadv_hardif_neigh_get cannot find the
> batadv_hardif_neigh_node for an neigh_addr due to some other list
> operations taking place at the same time.
> 
> Instead add a batadv_hardif_neigh_node pointer directly in
> batadv_neigh_node which will be used for the reference counter decremented
> on release of batadv_neigh_node.
> 
> Fixes: fed2826b490c ("batman-adv: add list of unique single hop neighbors
> per hard-interface") Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> See https://www.open-mesh.org/issues/242
> 
> v1:
>  - Remove the old code blocks
>  - make the _put unconditional
> ---
>  net/batman-adv/originator.c | 16 +++++-----------
>  net/batman-adv/types.h      |  2 ++
>  2 files changed, 7 insertions(+), 11 deletions(-)

Applied in revision a198a23.

Thanks,
Marek

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