Re: [PATCH wireless v2 1/2] wifi: mac80211: Update skb's control block key in ieee80211_tx_dequeue()

[Remi Pommarel <repk@triplefau.lt>]

On Thu, Jul 17, 2025 at 03:46:00PM +0200, Johannes Berg wrote:
> Hi,
> 
> On Thu, 2025-07-17 at 15:21 +0200, Remi Pommarel wrote:
> > I have ordered a mt7921 card so I could reproduce this and finally took
> > time to debug that. 
> 
> Oh wow, talk about dedication. Thank you!
> 
> > The issue comes to the fact that mt7921 uses 802.11
> > encapsulation offloading and as such we are calling
> > ieee80211_tx_h_select_key() on a 802.3 frame.
> 
> Oh... Guess we could've thought about that, sorry. Though I would've
> thought ath12k will also do that. Maybe not in the config you were
> seeing the issue in?

I've mainly tested on ath*k HW. Either without 802.11 encapsulation HW
offloading or with it but only on ath12k and it seems that this driver
does not need the key in this mode. After a quick look into ath11k and
10k that also seems to be the case for those chips.

For the record, if I am not mistaken, ath12k driver does not seem to
support 802.11 encaps HW offloading mainline yet, I do seem to have some
vendor patches to support it though.

> 
> > This function casts the skb data as a 802.11 header regardless the skb
> > is 802.11 or not in order to decide if the info->control.hw_key needs to
> > be set. So the hw_key is likely to remain NULL in ieee80211_tx_dequeue()
> > and because mt7921 driver needs this key to be valid data frames are
> > dropped.
> > 
> > Will send a patch so that ieee80211_tx_h_select_key() does not try to
> > get info from a ieee80211_hdr mapped on 802.3 packet data (i.e. when
> > IEEE80211_TX_CTL_HW_80211_ENCAP is set).
> > 
> 
> Sounds good!
> 
> johannes

-- 
Remi