linux-kernel - [PATCH 4.4 28/91] wil6210: fix deadlock when using fw_no

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Message-Id: <20170804231557.440235465@linuxfoundation.org>
Date:   Fri,  4 Aug 2017 16:15:24 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Lior David <qca_liord@....qualcomm.com>,
        Maya Erez <qca_merez@....qualcomm.com>,
        Kalle Valo <kvalo@....qualcomm.com>,
        Amit Pundir <amit.pundir@...aro.org>
Subject: [PATCH 4.4 28/91] wil6210: fix deadlock when using fw_no_recovery option

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lior David <qca_liord@....qualcomm.com>

commit dfb5b098e0f40b68aa07f2ec55f4dd762efefbfa upstream.

When FW crashes with no_fw_recovery option, driver
waits for manual recovery with wil->mutex held, this
can easily create deadlocks.
Fix the problem by moving the wait outside the lock.

Signed-off-by: Lior David <qca_liord@....qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@....qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@....qualcomm.com>
Signed-off-by: Amit Pundir <amit.pundir@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/net/wireless/ath/wil6210/main.c |   15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

--- a/drivers/net/wireless/ath/wil6210/main.c
+++ b/drivers/net/wireless/ath/wil6210/main.c
@@ -330,18 +330,19 @@ static void wil_fw_error_worker(struct w
 
 	wil->last_fw_recovery = jiffies;
 
+	wil_info(wil, "fw error recovery requested (try %d)...\n",
+		 wil->recovery_count);
+	if (!no_fw_recovery)
+		wil->recovery_state = fw_recovery_running;
+	if (wil_wait_for_recovery(wil) != 0)
+		return;
+
 	mutex_lock(&wil->mutex);
 	switch (wdev->iftype) {
 	case NL80211_IFTYPE_STATION:
 	case NL80211_IFTYPE_P2P_CLIENT:
 	case NL80211_IFTYPE_MONITOR:
-		wil_info(wil, "fw error recovery requested (try %d)...\n",
-			 wil->recovery_count);
-		if (!no_fw_recovery)
-			wil->recovery_state = fw_recovery_running;
-		if (0 != wil_wait_for_recovery(wil))
-			break;
-
+		/* silent recovery, upper layers will see disconnect */
 		__wil_down(wil);
 		__wil_up(wil);
 		break;