Subject: Re: [PATCH] mt76: fix potential NULL pointer dereference in mt76_stop_tx_queues

From: Kalle Valo <[email-masked]>
Date: Sat, 17 Nov 2018 13:13:37 +0200

Lorenzo Bianconi <[email-masked]> writes:

> Starting from mac80211 commit adf8ed01e4fd ("mac80211: add an optional
> TXQ for other PS-buffered frames") and commit 0eeb2b674f05 ("mac80211:
> add an option for station management TXQ") a new per-sta queue has been
> introduced for bufferable management frames.
> sta->txq[IEEE80211_NUM_TIDS] is initialized just if the driver reports
> the following hw flags:
> - IEEE80211_HW_STA_MMPDU_TXQ
> - IEEE80211_HW_BUFF_MMPDU_TXQ
> This can produce a NULL pointer dereference in mt76_stop_tx_queues
> since mt76 iterates on all available sta tx queues assuming they are
> initialized by mac80211. This issue has been spotted analyzing the code
> (it has not triggered any crash yet)
>
> Signed-off-by: Lorenzo Bianconi <[email-masked]>

A very good commit log, thanks for that!

> This patch is for 4.20

Ok, I'll wait for review comments and then queue this for 4.20.

BTW, it would make my patch sorting easier if you could add a release
label in the subject:

[PATCH 4.20] mt76: fix potential NULL pointer dereference in mt76_stop_tx_queues

More info:

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches#tree_labels

-- 
Kalle Valo