From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757049Ab0LHB60 (ORCPT ); Tue, 7 Dec 2010 20:58:26 -0500 Received: from kroah.org ([198.145.64.141]:48477 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756858Ab0LHA70 (ORCPT ); Tue, 7 Dec 2010 19:59:26 -0500 X-Mailbox-Line: From gregkh@clark.site Tue Dec 7 16:57:24 2010 Message-Id: <20101208005724.488697200@clark.site> User-Agent: quilt/0.48-11.2 Date: Tue, 07 Dec 2010 16:56:48 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Ben Greear , Kyungwan Nam , "Luis R. Rodriguez" , "John W. Linville" Subject: [031/289] ath9k: add locking for stopping RX In-Reply-To: <20101208005821.GA2922@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.36-stable review patch. If anyone has any objections, please let us know. ------------------ From: Luis R. Rodriguez commit 1e450285281bdf766272c181ecd43d4f2f0711ce upstream. ath9k locks for starting RX but not for stopping RX. We could potentially run into a situation where tried to stop RX but immediately started RX. This allows for races on the the RX engine deciding what buffer we last left off on and could potentially cause ath9k to DMA into already free'd memory or in the worst case at a later time to already given memory to other drivers. Fix this by locking stopping RX. This is part of a series that will help resolve the bug: https://bugzilla.kernel.org/show_bug.cgi?id=14624 For more details about this issue refer to: http://marc.info/?l=linux-wireless&m=128629803703756&w=2 Cc: Ben Greear Cc: Kyungwan Nam Signed-off-by: Luis R. Rodriguez Tested-by: Ben Greear Signed-off-by: John W. Linville Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/ath/ath9k/recv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/net/wireless/ath/ath9k/recv.c +++ b/drivers/net/wireless/ath/ath9k/recv.c @@ -297,10 +297,8 @@ static void ath_edma_start_recv(struct a static void ath_edma_stop_recv(struct ath_softc *sc) { - spin_lock_bh(&sc->rx.rxbuflock); ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_HP); ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_LP); - spin_unlock_bh(&sc->rx.rxbuflock); } int ath_rx_init(struct ath_softc *sc, int nbufs) @@ -508,6 +506,7 @@ bool ath_stoprecv(struct ath_softc *sc) struct ath_hw *ah = sc->sc_ah; bool stopped; + spin_lock_bh(&sc->rx.rxbuflock); ath9k_hw_stoppcurecv(ah); ath9k_hw_setrxfilter(ah, 0); stopped = ath9k_hw_stopdmarecv(ah); @@ -516,6 +515,7 @@ bool ath_stoprecv(struct ath_softc *sc) ath_edma_stop_recv(sc); else sc->rx.rxlink = NULL; + spin_unlock_bh(&sc->rx.rxbuflock); return stopped; }