It can happen that a tt_req_node list entry was already removed from tt.req_list when batadv_send_tt_request reaches the end of the function. The reference counter was already reduced by 1 for the list entry and thus the reference counter is not allowed to be reduced again. Otherwise, the entry is freed too early and the next batadv_tt_req_node_put in this function will operate on freed memory.

Fixes: cea194d90b11 ("batman-adv: improved client announcement mechanism") Signed-off-by: Sven Eckelmann sven@narfation.org --- net/batman-adv/translation-table.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index 3c32f5f..7e6df7a 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -2639,11 +2639,13 @@ static bool batadv_send_tt_request(struct batadv_priv *bat_priv, out: if (primary_if) batadv_hardif_put(primary_if); + if (ret && tt_req_node) { spin_lock_bh(&bat_priv->tt.req_list_lock); - /* hlist_del_init() verifies tt_req_node still is in the list */ - hlist_del_init(&tt_req_node->list); - batadv_tt_req_node_put(tt_req_node); + if (!hlist_unhashed(&tt_req_node->list)) { + hlist_del_init(&tt_req_node->list); + batadv_tt_req_node_put(tt_req_node); + } spin_unlock_bh(&bat_priv->tt.req_list_lock); }