[PATCH 10/14] batman-adv: protect tt_local_entry from concurrent delete events
From: Antonio Quartulli <hidden>
Date: 2015-08-04 16:52:27
Subsystem:
batman advanced, the rest · Maintainers:
Marek Lindner, Simon Wunderlich, Antonio Quartulli, Sven Eckelmann, Linus Torvalds
From: Marek Lindner <redacted>
The tt_local_entry deletion performed in batadv_tt_local_remove() was neither
protecting against simultaneous deletes nor checking whether the element was
still part of the list before calling hlist_del_rcu().
Replacing the hlist_del_rcu() call with batadv_hash_remove() provides adequate
protection via hash spinlocks as well as an is-element-still-in-hash check to
avoid 'blind' hash removal.
Fixes: 068ee6e204e1 ("batman-adv: roaming handling mechanism redesign")
Reported-by: alfonsname@web.de
Signed-off-by: Marek Lindner <redacted>
Signed-off-by: Antonio Quartulli <redacted>
---
net/batman-adv/translation-table.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 2db3093..cb2a2d1 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c@@ -1038,6 +1038,7 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv, struct batadv_tt_local_entry *tt_local_entry; uint16_t flags, curr_flags = BATADV_NO_FLAGS; struct batadv_softif_vlan *vlan; + void *tt_entry_exists; tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr, vid); if (!tt_local_entry)
@@ -1065,7 +1066,15 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv, * immediately purge it */ batadv_tt_local_event(bat_priv, tt_local_entry, BATADV_TT_CLIENT_DEL); - hlist_del_rcu(&tt_local_entry->common.hash_entry); + + tt_entry_exists = batadv_hash_remove(bat_priv->tt.local_hash, + batadv_compare_tt, + batadv_choose_tt, + &tt_local_entry->common); + if (!tt_entry_exists) + goto out; + + /* extra call to free the local tt entry */ batadv_tt_local_entry_free_ref(tt_local_entry); /* decrease the reference held for this vlan */
--
2.5.0