From 884a963fa1c828a5c5fa7a46b2877dd463bfd47c Mon Sep 17 00:00:00 2001 From: Rajkumar Manoharan Date: Tue, 7 Dec 2010 17:42:18 +0530 Subject: [PATCH] ath9k: fix beacon resource related race condition The beacon tasklet is accesssing the bslot info for beacon generation. Meanwhile the same slot can be freed on interface deletion. Current the remove_interface disables the beacon alert after freeing the slot. This may leads to null pointer access. This patch disables SWBA and kills the beacon tasklet to prevent access to the slot to be freed. After releasing the slot, swba will be enabled again upon the availablity of beaconing interfaces. Signed-off-by: Rajkumar Manoharan Signed-off-by: John W. Linville --- drivers/net/wireless/ath/ath9k/main.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c index 928ef68ab40c..c0c3464d3a86 100644 --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -1520,8 +1520,6 @@ static void ath9k_remove_interface(struct ieee80211_hw *hw, struct ath_softc *sc = aphy->sc; struct ath_common *common = ath9k_hw_common(sc->sc_ah); struct ath_vif *avp = (void *)vif->drv_priv; - bool bs_valid = false; - int i; ath_print(common, ATH_DBG_CONFIG, "Detach Interface\n"); @@ -1535,26 +1533,21 @@ static void ath9k_remove_interface(struct ieee80211_hw *hw, if ((sc->sc_ah->opmode == NL80211_IFTYPE_AP) || (sc->sc_ah->opmode == NL80211_IFTYPE_ADHOC) || (sc->sc_ah->opmode == NL80211_IFTYPE_MESH_POINT)) { + /* Disable SWBA interrupt */ + sc->sc_ah->imask &= ~ATH9K_INT_SWBA; ath9k_ps_wakeup(sc); + ath9k_hw_set_interrupts(sc->sc_ah, sc->sc_ah->imask); ath9k_hw_stoptxdma(sc->sc_ah, sc->beacon.beaconq); ath9k_ps_restore(sc); + tasklet_kill(&sc->bcon_tasklet); } ath_beacon_return(sc, avp); sc->sc_flags &= ~SC_OP_BEACONS; - for (i = 0; i < ARRAY_SIZE(sc->beacon.bslot); i++) { - if (sc->beacon.bslot[i] == vif) { - printk(KERN_DEBUG "%s: vif had allocated beacon " - "slot\n", __func__); - sc->beacon.bslot[i] = NULL; - sc->beacon.bslot_aphy[i] = NULL; - } else if (sc->beacon.bslot[i]) - bs_valid = true; - } - if (!bs_valid && (sc->sc_ah->imask & ATH9K_INT_SWBA)) { - /* Disable SWBA interrupt */ - sc->sc_ah->imask &= ~ATH9K_INT_SWBA; + if (sc->nbcnvifs) { + /* Re-enable SWBA interrupt */ + sc->sc_ah->imask |= ATH9K_INT_SWBA; ath9k_ps_wakeup(sc); ath9k_hw_set_interrupts(sc->sc_ah, sc->sc_ah->imask); ath9k_ps_restore(sc);