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[24.9.64.241]) by smtp.gmail.com with ESMTPSA id c2sm3480594ilk.32.2021.02.11.18.13.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Feb 2021 18:13:12 -0800 (PST) From: Shuah Khan To: kvalo@codeaurora.org, davem@davemloft.net, kuba@kernel.org Cc: Shuah Khan , ath9k-devel@qca.qualcomm.com, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] ath9k: hold RCU lock when calling ieee80211_find_sta_by_ifaddr() Date: Thu, 11 Feb 2021 19:13:05 -0700 Message-Id: <1cfa036227cfa9fdd04316c01e1d754f13a70d9e.1613090339.git.skhan@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org 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 --- - 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)