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: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Reported-by: Huang Shijie <b32955@freescale.com> Signed-off-by: Felipe Balbi <balbi@ti.com> Tested-by: Andreas Bießmann <andreas@biessmann.de> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -118,10 +118,6 @@ static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
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int hci_uart_tx_wakeup(struct hci_uart *hu)
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{
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struct tty_struct *tty = hu->tty;
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struct hci_dev *hdev = hu->hdev;
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struct sk_buff *skb;
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if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
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set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
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return 0;
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@ -129,6 +125,22 @@ int hci_uart_tx_wakeup(struct hci_uart *hu)
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BT_DBG("");
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schedule_work(&hu->write_work);
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return 0;
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}
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static void hci_uart_write_work(struct work_struct *work)
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{
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struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
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struct tty_struct *tty = hu->tty;
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struct hci_dev *hdev = hu->hdev;
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struct sk_buff *skb;
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/* REVISIT: should we cope with bad skbs or ->write() returning
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* and error value ?
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*/
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restart:
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clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
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@ -153,7 +165,6 @@ restart:
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goto restart;
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clear_bit(HCI_UART_SENDING, &hu->tx_state);
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return 0;
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}
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static void hci_uart_init_work(struct work_struct *work)
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@ -282,6 +293,7 @@ static int hci_uart_tty_open(struct tty_struct *tty)
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tty->receive_room = 65536;
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INIT_WORK(&hu->init_ready, hci_uart_init_work);
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INIT_WORK(&hu->write_work, hci_uart_write_work);
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spin_lock_init(&hu->rx_lock);
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@ -319,6 +331,8 @@ static void hci_uart_tty_close(struct tty_struct *tty)
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if (hdev)
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hci_uart_close(hdev);
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cancel_work_sync(&hu->write_work);
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if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
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if (hdev) {
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if (test_bit(HCI_UART_REGISTERED, &hu->flags))
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@ -68,6 +68,7 @@ struct hci_uart {
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unsigned long hdev_flags;
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struct work_struct init_ready;
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struct work_struct write_work;
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struct hci_uart_proto *proto;
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void *priv;
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