[PATCH 4.19 067/264] Bluetooth: hci_uart: Cancel init work before unregistering

Greg Kroah-Hartman
2020-10-27T18:03:19Z

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 efeb8137ec67f..48560e646e53e 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -545,6 +545,7 @@ 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 d3fb0d657fa52..7b3aade431e5e 100644
--- a/drivers/bluetooth/hci_serdev.c
+++ b/drivers/bluetooth/hci_serdev.c
@@ -369,6 +369,8 @@ 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