From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120411231309.894025817@linuxfoundation.org> Date: Wed, 11 Apr 2012 16:13:22 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "jan p. springer" , Stanislaw Gruszka , "John W. Linville" Subject: [ 15/42] mac80211: fix possible tid_rx->reorder_timer use after free In-Reply-To: <20120411231443.GA808@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stanislaw Gruszka commit d72308bff5c2fa207949a5925b020bce74495e33 upstream. Is possible that we will arm the tid_rx->reorder_timer after del_timer_sync() in ___ieee80211_stop_rx_ba_session(). We need to stop timer after RCU grace period finish, so move it to ieee80211_free_tid_rx(). Timer will not be armed again, as rcu_dereference(sta->ampdu_mlme.tid_rx[tid]) will return NULL. Debug object detected problem with the following warning: ODEBUG: free active (active state 0) object type: timer_list hint: sta_rx_agg_reorder_timer_expired+0x0/0xf0 [mac80211] Bug report (with all warning messages): https://bugzilla.redhat.com/show_bug.cgi?id=804007 Reported-by: "jan p. springer" Signed-off-by: Stanislaw Gruszka Signed-off-by: John W. Linville Signed-off-by: Greg Kroah-Hartman --- net/mac80211/agg-rx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/mac80211/agg-rx.c +++ b/net/mac80211/agg-rx.c @@ -48,6 +48,8 @@ static void ieee80211_free_tid_rx(struct container_of(h, struct tid_ampdu_rx, rcu_head); int i; + del_timer_sync(&tid_rx->reorder_timer); + for (i = 0; i < tid_rx->buf_size; i++) dev_kfree_skb(tid_rx->reorder_buf[i]); kfree(tid_rx->reorder_buf); @@ -87,7 +89,6 @@ void ___ieee80211_stop_rx_ba_session(str tid, 0, reason); del_timer_sync(&tid_rx->session_timer); - del_timer_sync(&tid_rx->reorder_timer); call_rcu(&tid_rx->rcu_head, ieee80211_free_tid_rx); }