Re: [PATCH] mt76: hold RCU lock when calling ieee80211_find_sta_by_ifaddr()

[Shuah Khan]

On 2/11/21 10:36 PM, Felix Fietkau wrote:
> On 2021-02-12 03:13, Shuah Khan wrote:
> > ieee80211_find_sta_by_ifaddr() must be called under the RCU lock and
> > the resulting pointer is only valid under RCU lock as well.
> >
> > Fix mt76_check_sta() to hold RCU read lock before it calls
> > ieee80211_find_sta_by_ifaddr() and release it when the resulting
> > pointer is no longer needed.
> >
> > This problem was found while reviewing code to debug RCU warn from
> > ath10k_wmi_tlv_parse_peer_stats_info() and a subsequent manual audit
> > of other callers of ieee80211_find_sta_by_ifaddr() that don't hold
> > RCU read lock.
> >
> > Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
> If I'm not mistaken, this patch is unnecessary. mt76_check_sta is only
> called from mt76_rx_poll_complete, which itself is only called under RCU
> lock.

Yes. You are right. I checked the caller of this routine and didn't
go further up. :)

thanks,
-- Shuah