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>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-sta.c b/drivers/net/wireless/iwlwifi/iwl-sta.c
index 0a67b2fa52a1..4776323b1eba 100644
--- 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));