RE: On 021d53a3d87e ("wifi: mac80211: fix NULL dereference at band check in starting tx ba session")

[Zong-Zhe Yang <kevin_yang@realtek.com>]

Dmitry Antipov <dmantipov@yandex.ru> wrote:
> 
> Looking at 021d53a3d87e ("wifi: mac80211: fix NULL dereference at band check in starting tx
> ba session"), can the following be useful for older (e.g. 5.10) kernels without any MLO
> support?
> 
> diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c index
> 4b4ab1961068..1a89ba2aecaa 100644
> --- a/net/mac80211/agg-tx.c
> +++ b/net/mac80211/agg-tx.c
> @@ -595,7 +595,8 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16
> tid,
>                 return -EINVAL;
> 
>         if (!pubsta->ht_cap.ht_supported &&
> -           sta->sdata->vif.bss_conf.chandef.chan->band != NL80211_BAND_6GHZ)
> +           !pubsta->vht_cap.vht_supported &&
> +           !pubsta->he_cap.has_he)
>                 return -EINVAL;
> 
>         if (WARN_ON_ONCE(!local->ops->ampdu_action))
> 
> Dmitry
> 

Without MLO, no NULL dereference here, and the original logic is workable (though not very intuitive).
So, to me, it doesn't seem much necessary for older kernels.