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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Samuel Holland <samuel@sholland.org>,
        Marcel Holtmann <marcel@holtmann.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.8 156/633] Bluetooth: hci_uart: Cancel init work before unregistering
Date:   Tue, 27 Oct 2020 14:48:19 +0100
Message-Id: <20201027135530.010044258@linuxfoundation.org>
In-Reply-To: <20201027135522.655719020@linuxfoundation.org>
References: <20201027135522.655719020@linuxfoundation.org>
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From: Samuel Holland <samuel@sholland.org>

[ Upstream commit 3b799254cf6f481460719023d7a18f46651e5e7f ]

If hci_uart_tty_close() or hci_uart_unregister_device() is called while
hu->init_ready is scheduled, hci_register_dev() could be called after
the hci_uart is torn down. Avoid this by ensuring the work is complete
or canceled before checking the HCI_UART_REGISTERED flag.

Fixes: 9f2aee848fe6 ("Bluetooth: Add delayed init sequence support for UART controllers")
Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/bluetooth/hci_ldisc.c  | 1 +
 drivers/bluetooth/hci_serdev.c | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index 85a30fb9177bb..f83d67eafc9f0 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -538,6 +538,7 @@ static void hci_uart_tty_close(struct tty_struct *tty)
 		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
 		percpu_up_write(&hu->proto_lock);
 
+		cancel_work_sync(&hu->init_ready);
 		cancel_work_sync(&hu->write_work);
 
 		if (hdev) {
diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c
index 7b233312e723f..3977bba485c22 100644
--- a/drivers/bluetooth/hci_serdev.c
+++ b/drivers/bluetooth/hci_serdev.c
@@ -355,6 +355,8 @@ void hci_uart_unregister_device(struct hci_uart *hu)
 	struct hci_dev *hdev = hu->hdev;
 
 	clear_bit(HCI_UART_PROTO_READY, &hu->flags);
+
+	cancel_work_sync(&hu->init_ready);
 	if (test_bit(HCI_UART_REGISTERED, &hu->flags))
 		hci_unregister_dev(hdev);
 	hci_free_dev(hdev);
-- 
2.25.1