printk(KERN_ERR "Unable to create debugfs files\n");
 
        spin_lock_init(&sc->sc_resetlock);
+       mutex_init(&sc->mutex);
        tasklet_init(&sc->intr_tq, ath9k_tasklet, (unsigned long)sc);
        tasklet_init(&sc->bcon_tasklet, ath9k_beacon_tasklet,
                     (unsigned long)sc);
        struct ath_softc *sc = hw->priv;
        struct ieee80211_conf *conf = &hw->conf;
 
+       mutex_lock(&sc->mutex);
        if (changed & (IEEE80211_CONF_CHANGE_CHANNEL |
                       IEEE80211_CONF_CHANGE_HT)) {
                struct ieee80211_channel *curchan = hw->conf.channel;
                if (pos == -1) {
                        DPRINTF(sc, ATH_DBG_FATAL, "Invalid channel: %d\n",
                                curchan->center_freq);
+                       mutex_unlock(&sc->mutex);
                        return -EINVAL;
                }
 
 
                if (ath_set_channel(sc, &sc->sc_ah->ah_channels[pos]) < 0) {
                        DPRINTF(sc, ATH_DBG_FATAL, "Unable to set channel\n");
+                       mutex_unlock(&sc->mutex);
                        return -EINVAL;
                }
 
        if (changed & IEEE80211_CONF_CHANGE_POWER)
                sc->sc_config.txpowlimit = 2 * conf->power_level;
 
+       mutex_unlock(&sc->mutex);
        return 0;
 }