From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753562AbaCaAOA (ORCPT ); Sun, 30 Mar 2014 20:14:00 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36413 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753053AbaC3XZC (ORCPT ); Sun, 30 Mar 2014 19:25:02 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Stanislaw Gruszka" , "John W. Linville" Date: Mon, 31 Mar 2014 00:23:35 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 136/200] ath9k: protect tid->sched check In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.56-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Stanislaw Gruszka commit 21f8aaee0c62708654988ce092838aa7df4d25d8 upstream. We check tid->sched without a lock taken on ath_tx_aggr_sleep(). That is race condition which can result of doing list_del(&tid->list) twice (second time with poisoned list node) and cause crash like shown below: [424271.637220] BUG: unable to handle kernel paging request at 00100104 [424271.637328] IP: [] ath_tx_aggr_sleep+0x62/0xe0 [ath9k] ... [424271.639953] Call Trace: [424271.639998] [] ? ath9k_get_survey+0x110/0x110 [ath9k] [424271.640083] [] ath9k_sta_notify+0x42/0x50 [ath9k] [424271.640177] [] sta_ps_start+0x8f/0x1c0 [mac80211] [424271.640258] [] ? free_compound_page+0x2e/0x40 [424271.640346] [] ieee80211_rx_handlers+0x9d5/0x2340 [mac80211] [424271.640437] [] ? kmem_cache_free+0x1d8/0x1f0 [424271.640510] [] ? kfree_skbmem+0x34/0x90 [424271.640578] [] ? put_page+0x2c/0x40 [424271.640640] [] ? kfree_skbmem+0x34/0x90 [424271.640706] [] ? kfree_skbmem+0x34/0x90 [424271.640787] [] ? ieee80211_rx_handlers_result+0x73/0x1d0 [mac80211] [424271.640897] [] ieee80211_prepare_and_rx_handle+0x520/0xad0 [mac80211] [424271.641009] [] ? ieee80211_rx_handlers+0x2ed/0x2340 [mac80211] [424271.641104] [] ? ip_output+0x7e/0xd0 [424271.641182] [] ieee80211_rx+0x307/0x7c0 [mac80211] [424271.641266] [] ath_rx_tasklet+0x88e/0xf70 [ath9k] [424271.641358] [] ? ieee80211_rx+0x1dc/0x7c0 [mac80211] [424271.641445] [] ath9k_tasklet+0xcb/0x130 [ath9k] Bug report: https://bugzilla.kernel.org/show_bug.cgi?id=70551 Reported-and-tested-by: Max Sydorenko Signed-off-by: Stanislaw Gruszka Signed-off-by: John W. Linville [bwh: Backported to 3.2: - Adjust context - Use spin_unlock_bh() directly] Signed-off-by: Ben Hutchings --- drivers/net/wireless/ath/ath9k/xmit.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/drivers/net/wireless/ath/ath9k/xmit.c +++ b/drivers/net/wireless/ath/ath9k/xmit.c @@ -1176,14 +1176,16 @@ void ath_tx_aggr_sleep(struct ieee80211_ for (tidno = 0, tid = &an->tid[tidno]; tidno < WME_NUM_TID; tidno++, tid++) { - if (!tid->sched) - continue; - ac = tid->ac; txq = ac->txq; spin_lock_bh(&txq->axq_lock); + if (!tid->sched) { + spin_unlock_bh(&txq->axq_lock); + continue; + } + buffered = !skb_queue_empty(&tid->buf_q); tid->sched = false;