Re: [PATCH 1/2] ath9k: hold RCU lock when calling ieee80211_find_sta_by_ifaddr()

From: Felix Fietkau
Date: Fri Feb 12 2021 - 01:33:01 EST


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 ath_tx_process_buffer() 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>
This patch seems unnecessary as well. All callers of
ath_tx_process_buffer seem to hold the RCU read lock already.

- Felix