| Message ID | 1cfa036227cfa9fdd04316c01e1d754f13a70d9e.1613090339.git.skhan@linuxfoundation.org |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] ath9k: hold RCU lock when calling ieee80211_find_sta_by_ifaddr() | expand |
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@linuxfoundation.org> > 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
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)
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@linuxfoundation.org> --- - 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(+)