From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756498Ab2KNFvN (ORCPT ); Wed, 14 Nov 2012 00:51:13 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:55263 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756458Ab2KNFvH (ORCPT ); Wed, 14 Nov 2012 00:51:07 -0500 Message-Id: <20121114053938.462480058@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Wed, 14 Nov 2012 05:40:06 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Felix Fietkau , "John W. Linville" Subject: [ 33/82] ath9k: fix stale pointers potentially causing access to freed skbs In-Reply-To: <20121114053933.726869752@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 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-stable review patch. If anyone has any objections, please let me know. ------------------ From: Felix Fietkau commit 8c6e30936a7893a85f6222084f0f26aceb81137a upstream. bf->bf_next is only while buffers are chained as part of an A-MPDU in the tx queue. When a tid queue is flushed (e.g. on tearing down an aggregation session), frames can be enqueued again as normal transmission, without bf_next being cleared. This can lead to the old pointer being dereferenced again later. This patch might fix crashes and "Failed to stop TX DMA!" messages. Signed-off-by: Felix Fietkau Signed-off-by: John W. Linville [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/net/wireless/ath/ath9k/xmit.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/net/wireless/ath/ath9k/xmit.c +++ b/drivers/net/wireless/ath/ath9k/xmit.c @@ -288,6 +288,7 @@ static struct ath_buf *ath_tx_get_buffer } bf = list_first_entry(&sc->tx.txbuf, struct ath_buf, list); + bf->bf_next = NULL; list_del(&bf->list); spin_unlock_bh(&sc->tx.txbuflock); @@ -1710,6 +1711,7 @@ static void ath_tx_send_normal(struct at if (tid) INCR(tid->seq_start, IEEE80211_SEQ_MAX); + bf->bf_next = NULL; bf->bf_lastbf = bf; ath_tx_fill_desc(sc, bf, txq, fi->framelen); ath_tx_txqaddbuf(sc, txq, &bf_head, false);