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[24.9.64.241]) by smtp.gmail.com with ESMTPSA id i20sm5180328ilc.2.2021.02.12.15.28.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Feb 2021 15:28:50 -0800 (PST) From: Shuah Khan To: peterz@infradead.org, mingo@redhat.com, will@kernel.org, kvalo@codeaurora.org, davem@davemloft.net, kuba@kernel.org Cc: Shuah Khan , ath10k@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] ath10k: detect conf_mutex held ath10k_drain_tx() calls Date: Fri, 12 Feb 2021 16:28:43 -0700 Message-Id: <0686097db95ae32ce6805e5163798d912b394f37.1613171185.git.skhan@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ath10k_drain_tx() must not be called with conf_mutex held as workers can use that also. Add call to lockdep_assert_not_held() on conf_mutex to detect if conf_mutex is held by the caller. The idea for this patch stemmed from coming across the comment block above the ath10k_drain_tx() while reviewing the conf_mutex holds during to debug the conf_mutex lock assert in ath10k_debug_fw_stats_request(). Adding detection to assert on conf_mutex hold will help detect incorrect usages that could lead to locking problems when async worker routines try to call this routine. Link: https://lore.kernel.org/linux-wireless/871rdmu9z9.fsf@codeaurora.org/ Signed-off-by: Shuah Khan --- drivers/net/wireless/ath/ath10k/mac.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c index c202b167d8c6..7de05b679ad2 100644 --- a/drivers/net/wireless/ath/ath10k/mac.c +++ b/drivers/net/wireless/ath/ath10k/mac.c @@ -4728,6 +4728,8 @@ static void ath10k_mac_op_wake_tx_queue(struct ieee80211_hw *hw, /* Must not be called with conf_mutex held as workers can use that also. */ void ath10k_drain_tx(struct ath10k *ar) { + lockdep_assert_not_held(&ar->conf_mutex); + /* make sure rcu-protected mac80211 tx path itself is drained */ synchronize_net(); -- 2.27.0