drivers: wifi: Handle interface de-initialization races

When the interface is being brought down there can be number of races
conditions till the deletion is properly propagated, so, add NULL checks
to avoid crash.

E.g.,

  * Supplicant can still be deleting keys but interface is already
    removed in the driver
  * Networking stack sending TX packet

Avoiding the races completely will be handled later. As these can happen
till that time, no error logging is added.

Fixes SHEL-1982 partially.

Signed-off-by: Chaitanya Tata <[email protected]>

drivers/wifi/nrf700x/osal/fw_if/umac_if/src/event.c

@@ -156,16 +156,20 @@ static enum wifi_nrf_status umac_event_ctrl_process(struct wifi_nrf_fmac_dev_ctx
 	struct wifi_nrf_fmac_dev_ctx_def *def_dev_ctx = NULL;
 	struct wifi_nrf_fmac_priv_def *def_priv = NULL;
 
-	def_priv = wifi_fmac_priv(fmac_dev_ctx->fpriv);
-	def_dev_ctx = wifi_dev_priv(fmac_dev_ctx);
-
 	if (!fmac_dev_ctx || !event_data) {
 		wifi_nrf_osal_log_err(fmac_dev_ctx->fpriv->opriv,
 				      "%s: Invalid parameters\n",
 				      __func__);
 		goto out;
 	}
 
+	def_priv = wifi_fmac_priv(fmac_dev_ctx->fpriv);
+	def_dev_ctx = wifi_dev_priv(fmac_dev_ctx);
+
+	if (!def_priv || !def_dev_ctx) {
+		goto out;
+	}
+
 	umac_hdr = event_data;
 	if_id = umac_hdr->ids.wdev_id;
 	event_num = umac_hdr->cmd_evnt;

drivers/wifi/nrf700x/zephyr/src/zephyr_net_if.c

@@ -165,6 +165,10 @@ int wifi_nrf_if_send(const struct device *dev,
 
 	rpu_ctx_zep = vif_ctx_zep->rpu_ctx_zep;
 
+	if (!rpu_ctx_zep->rpu_ctx) {
+		goto out;
+	}
+
 	if ((vif_ctx_zep->if_carr_state != WIFI_NRF_FMAC_IF_CARR_STATE_ON) ||
 	    (!vif_ctx_zep->authorized && !is_eapol(pkt))) {
 		goto out;

drivers/wifi/nrf700x/zephyr/src/zephyr_wpa_supp_if.c

@@ -859,6 +859,13 @@ int wifi_nrf_wpa_supp_set_key(void *if_priv, const unsigned char *ifname, enum w
 	vif_ctx_zep = if_priv;
 	rpu_ctx_zep = vif_ctx_zep->rpu_ctx_zep;
 
+	/* Can happen in a positive case where "net if down" is completed, but WPA
+	 * supplicant is still deleting keys.
+	 */
+	if (!rpu_ctx_zep->rpu_ctx) {
+		goto out;
+	}
+
 	memset(&key_info, 0, sizeof(key_info));
 
 	if (alg != WPA_ALG_NONE) {