Re: [B.A.T.M.A.N.] batman-adv: gpf in batadv_slide_own_bcast_window

From: Marek Lindner
Date: Tue Feb 26 2013 - 00:59:23 EST

On Saturday, February 23, 2013 02:37:06 Sasha Levin wrote:
> I'm confused about how batadv_orig_hash_del_if removes an interface from
> the hashtable. I see the hashtable is using rcu to protect it, but when we
> delete an entry we free it straight away by calling
> batadv_orig_node_del_if() and not going through kfree_rcu().
> Is there a reason behind doing that, or might it be the cause of the
> problem we're seeing here?

Maybe I am overlooking something but it seems to me access to this memory is
protected by the same lock: orig_node->ogm_cnt_lock
Before batadv_orig_node_del_if() is called this lock is acquired and
batadv_slide_own_bcast_window() also attempts acquire the orig_node-
>ogm_cnt_lock spinlock before writing to this chunk of memory.

Do we know for certain that batadv_orig_hash_del_if() is involved or is that a
guess at this point ? If you ask me the next for-loop in
batadv_orig_hash_del_if() looks more suspicious than the first one. The
interfaces get renumbered without any protection. Could be a regression from
the orig_hash_lock removal (the comments refer to a now inexisting lock).

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at