iwlagn: fix race condition when reprogram sta

During reprogram stations, do not send link quality command.
uCode will crash if receive link quality command for invalid station

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

diff --git a/drivers/net/wireless/iwlwifi/iwl-sta.c b/drivers/net/wireless/iwlwifi/iwl-sta.c
index 0a67b2f..4776323 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-sta.c
+++ b/drivers/net/wireless/iwlwifi/iwl-sta.c
@@ -647,6 +647,7 @@ void iwl_reprogram_ap_sta(struct iwl_priv *priv, struct iwl_rxon_context *ctx)
        memcpy(&lq, priv->stations[sta_id].lq, sizeof(lq));
 
        active = priv->stations[sta_id].used & IWL_STA_UCODE_ACTIVE;
+       priv->stations[sta_id].used &= ~IWL_STA_DRIVER_ACTIVE;
        spin_unlock_irqrestore(&priv->sta_lock, flags);
 
        if (active) {
@@ -657,6 +658,10 @@ void iwl_reprogram_ap_sta(struct iwl_priv *priv, struct iwl_rxon_context *ctx)
                        IWL_ERR(priv, "failed to remove STA %pM (%d)\n",
                                priv->stations[sta_id].sta.sta.addr, ret);
        }
+       spin_lock_irqsave(&priv->sta_lock, flags);
+       priv->stations[sta_id].used |= IWL_STA_DRIVER_ACTIVE;
+       spin_unlock_irqrestore(&priv->sta_lock, flags);
+
        ret = iwl_send_add_sta(priv, &sta_cmd, CMD_SYNC);
        if (ret)
                IWL_ERR(priv, "failed to re-add STA %pM (%d)\n",
@@ -777,6 +782,14 @@ int iwl_send_lq_cmd(struct iwl_priv *priv, struct iwl_rxon_context *ctx,
        if (WARN_ON(lq->sta_id == IWL_INVALID_STATION))
                return -EINVAL;
 
+
+       spin_lock_irqsave(&priv->sta_lock, flags_spin);
+       if (!(priv->stations[lq->sta_id].used & IWL_STA_DRIVER_ACTIVE)) {
+               spin_unlock_irqrestore(&priv->sta_lock, flags_spin);
+               return -EINVAL;
+       }
+       spin_unlock_irqrestore(&priv->sta_lock, flags_spin);
+
        iwl_dump_lq_cmd(priv, lq);
        BUG_ON(init && (cmd.flags & CMD_ASYNC));