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>
---
- Note: This patch is compile tested. I don't have access to
hardware.
drivers/net/wireless/ath/ath9k/xmit.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index e60d4737fc6e..1d36aae3f7b6 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -701,6 +701,9 @@ static void ath_tx_process_buffer(struct ath_softc *sc, struct ath_txq *txq,
ts->ts_rateindex);
hdr = (struct ieee80211_hdr *) bf->bf_mpdu->data;
+
+ rcu_read_lock();
+
sta = ieee80211_find_sta_by_ifaddr(hw, hdr->addr1, hdr->addr2);
if (sta) {
struct ath_node *an = (struct ath_node *)sta->drv_priv;
@@ -725,6 +728,8 @@ static void ath_tx_process_buffer(struct ath_softc *sc, struct ath_txq *txq,
if (!flush)
ath_txq_schedule(sc, txq);
+
+ rcu_read_unlock();
}
static bool ath_lookup_legacy(struct ath_buf *bf)
--
2.27.0
