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Commit da64c27d authored by Felipe Balbi's avatar Felipe Balbi Committed by Greg Kroah-Hartman
Browse files

bluetooth: hci_ldisc: fix deadlock condition 



LDISCs shouldn't call tty->ops->write() from within
->write_wakeup().

->write_wakeup() is called with port lock taken and
IRQs disabled, tty->ops->write() will try to acquire
the same port lock and we will deadlock.

Acked-by: default avatarMarcel Holtmann <marcel@holtmann.org>
Reviewed-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Reported-by: default avatarHuang Shijie <b32955@freescale.com>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
Tested-by: default avatarAndreas Bießmann <andreas@biessmann.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 879eb9c3

drivers/bluetooth/hci_ldisc.c

+19 −5
Original line number Diff line number Diff line
@@ -118,10 +118,6 @@ static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu) 


int hci_uart_tx_wakeup(struct hci_uart *hu)

{

	struct tty_struct *tty = hu->tty;

	struct hci_dev *hdev = hu->hdev;

	struct sk_buff *skb;



	if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {

		set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);

		return 0;
@@ -129,6 +125,22 @@ int hci_uart_tx_wakeup(struct hci_uart *hu) 


	BT_DBG("");



	schedule_work(&hu->write_work);



	return 0;

}



static void hci_uart_write_work(struct work_struct *work)

{

	struct hci_uart *hu = container_of(work, struct hci_uart, write_work);

	struct tty_struct *tty = hu->tty;

	struct hci_dev *hdev = hu->hdev;

	struct sk_buff *skb;



	/* REVISIT: should we cope with bad skbs or ->write() returning

	 * and error value ?

	 */



restart:

	clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
@@ -153,7 +165,6 @@ int hci_uart_tx_wakeup(struct hci_uart *hu) 
		goto restart;



	clear_bit(HCI_UART_SENDING, &hu->tx_state);

	return 0;

}



static void hci_uart_init_work(struct work_struct *work)
@@ -282,6 +293,7 @@ static int hci_uart_tty_open(struct tty_struct *tty) 
	tty->receive_room = 65536;



	INIT_WORK(&hu->init_ready, hci_uart_init_work);

	INIT_WORK(&hu->write_work, hci_uart_write_work);



	spin_lock_init(&hu->rx_lock);
@@ -319,6 +331,8 @@ static void hci_uart_tty_close(struct tty_struct *tty) 
	if (hdev)

		hci_uart_close(hdev);



	cancel_work_sync(&hu->write_work);



	if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {

		if (hdev) {

			if (test_bit(HCI_UART_REGISTERED, &hu->flags))

drivers/bluetooth/hci_uart.h

+1 −0
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ struct hci_uart { 
	unsigned long		hdev_flags;



	struct work_struct	init_ready;

	struct work_struct	write_work;



	struct hci_uart_proto	*proto;

	void			*priv;