wifi: mac80211: ibss: stop transmit when merging IBSS

We disable the carrier, but that doesn't immediately take
effect, and as such a concurrent transmit can go into the
driver while drv_leave_ibss() is happening and confuse it.
Synchronize to avoid that.

Signed-off-by: Johannes Berg <[email protected]>
Signed-off-by: Miri Korenblit <[email protected]>
Link: https://patch.msgid.link/20250102161730.83b58167e80e.I538751fbe1b4302d20f6ed80afb024bca6a2dbf5@changeid
Signed-off-by: Johannes Berg <[email protected]>

Author: jmberg-intel

net/mac80211/ibss.c

@@ -245,6 +245,7 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 		sdata->vif.cfg.ibss_creator = false;
 		sdata->vif.bss_conf.enable_beacon = false;
 		netif_carrier_off(sdata->dev);
+		synchronize_net();
 		ieee80211_bss_info_change_notify(sdata,
 						 BSS_CHANGED_IBSS |
 						 BSS_CHANGED_BEACON_ENABLED);