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Date:   Mon, 4 Apr 2022 18:22:36 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        Ben Young Tae Kim <ytkim@qca.qualcomm.com>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH] Bluetooth: hci_qca: Use del_timer_sync() before freeing
Message-ID: <20220404182236.1caa174e@rorschach.local.home>
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[ Resending due to cut and paste failure of email address ]

From: Steven Rostedt (Google) <rostedt@goodmis.org>

While looking at a crash report on a timer list being corrupted, which
usually happens when a timer is freed while still active. This is
commonly triggered by code calling del_timer() instead of
del_timer_sync() just before freeing.

One possible culprit is the hci_qca driver, which does exactly that.

Cc: stable@vger.kernel.org
Fixes: 0ff252c1976da ("Bluetooth: hciuart: Add support QCA chipset for
UART") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index f6e91fb432a3..73a8c72b5aae 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -696,8 +696,8 @@ static int qca_close(struct hci_uart *hu)
 	skb_queue_purge(&qca->tx_wait_q);
 	skb_queue_purge(&qca->txq);
 	skb_queue_purge(&qca->rx_memdump_q);
-	del_timer(&qca->tx_idle_timer);
-	del_timer(&qca->wake_retrans_timer);
+	del_timer_sync(&qca->tx_idle_timer);
+	del_timer_sync(&qca->wake_retrans_timer);
 	destroy_workqueue(qca->workqueue);
 	qca->hu = NULL;