Re: [PATCH] rtw89: fix RCU usage in rtw89_core_txq_push() (was Re: [PATCH] mac80211: fix RCU usage in ieee80211_tx_h_select_key())

[Kalle Valo]

Jiri Kosina <jikos@xxxxxxxxxx> writes:

> On Tue, 15 Feb 2022, Johannes Berg wrote:
>
>> > 
>> > ieee80211_tx_h_select_key() is performing a series of RCU dereferences, 
>> > but none of the callers seems to be taking RCU read-side lock; let's 
>> > acquire the lock in ieee80211_tx_h_select_key() itself.
>> > 
>> but but ...
>> 
>> >   ieee80211_tx_dequeue+0x1a7/0x1260 [mac80211 911c23e2351c0ae60b597a67b1204a5ea955e365]
>> >   rtw89_core_txq_work+0x1a6/0x420 [rtw89_core b39ba493f2e517ad75e0f8187ecc24edf58bbbea]
>> 
>> /**
>>  * ieee80211_tx_dequeue - dequeue a packet from a software tx queue
>>  *
>>  * @hw: pointer as obtained from ieee80211_alloc_hw()
>>  * @txq: pointer obtained from station or virtual interface, or from
>>  *      ieee80211_next_txq()
>>  *
>>  * Returns the skb if successful, %NULL if no frame was available.
>>  *
>>  * Note that this must be called in an rcu_read_lock() critical section,
>>  * which can only be released after the SKB was handled. Some pointers in
>> [...]
>> 
>> -> driver bug?
>
> Right you are, thanks.
>
> CCing Ping-Ke Shih; find updated fix below.
>
>
>
>
> From: Jiri Kosina <jkosina@xxxxxxx>
> Subject: [PATCH] rtw89: fix RCU usage in rtw89_core_txq_push()
>
> ieee80211_tx_h_select_key() is performing a series of RCU dereferences,
> but rtw89_core_txq_push() is calling it (via ieee80211_tx_dequeue_ni())
> without RCU read-side lock held; fix that.

I think we have discussed this before, but patchwork can't handle
patches the way you embed them in email discussions:

https://patchwork.kernel.org/project/linux-wireless/patch/nycvar.YFH.7.76.2202151700540.11721@xxxxxxxxxxxxx/

Please resubmit.

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