From 7bf31d2cec2d9dfe94f1b4b11f72a13630e5e2d6 Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Wed, 20 Oct 2010 16:07:03 -0700 Subject: [PATCH] ath9k: add locking for stopping RX 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(-) diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c index 8cb228bb7553..a40651d1924f 100644 --- 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 ath_softc *sc) 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; } -- 2.34.1