From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Felix Fietkau , "John W. Linville" Subject: [ 01/38] ath9k: fix stale pointers potentially causing access to freed skbs Date: Wed, 14 Nov 2012 20:09:58 -0800 Message-Id: <20121115040933.003106614@linuxfoundation.org> In-Reply-To: <20121115040932.918082372@linuxfoundation.org> References: <20121115040932.918082372@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.0-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 Signed-off-by: Greg Kroah-Hartman --- 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 @@ -272,6 +272,7 @@ 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); @@ -1488,6 +1489,7 @@ 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; fi = get_frame_info(bf->bf_mpdu); ath_buf_set_rate(sc, bf, fi->framelen);