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bluetooth: hci_ldisc: fix deadlock condition

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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>
This commit is contained in:
Felipe Balbi 2014-04-23 09:58:26 -05:00 committed by Greg Kroah-Hartman
parent 879eb9c3f9
commit da64c27d3c
2 changed files with 20 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
drivers/bluetooth/hci_ldisc.c
View File

@ -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) 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)) { if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state); set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
return 0; return 0;
@ -129,6 +125,22 @@ int hci_uart_tx_wakeup(struct hci_uart *hu)
BT_DBG(""); 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: restart:
clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state); clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
@ -153,7 +165,6 @@ restart:
goto restart; goto restart;
clear_bit(HCI_UART_SENDING, &hu->tx_state); clear_bit(HCI_UART_SENDING, &hu->tx_state);
return 0;
} }
static void hci_uart_init_work(struct work_struct *work) 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; tty->receive_room = 65536;
INIT_WORK(&hu->init_ready, hci_uart_init_work); INIT_WORK(&hu->init_ready, hci_uart_init_work);
INIT_WORK(&hu->write_work, hci_uart_write_work);
spin_lock_init(&hu->rx_lock); spin_lock_init(&hu->rx_lock);
@ -319,6 +331,8 @@ static void hci_uart_tty_close(struct tty_struct *tty)
if (hdev) if (hdev)
hci_uart_close(hdev); hci_uart_close(hdev);
cancel_work_sync(&hu->write_work);
if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) { if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
if (hdev) { if (hdev) {
if (test_bit(HCI_UART_REGISTERED, &hu->flags)) if (test_bit(HCI_UART_REGISTERED, &hu->flags))

1
drivers/bluetooth/hci_uart.h
View File

@ -68,6 +68,7 @@ struct hci_uart {
unsigned long hdev_flags; unsigned long hdev_flags;
struct work_struct init_ready; struct work_struct init_ready;
struct work_struct write_work;
struct hci_uart_proto *proto; struct hci_uart_proto *proto;
void *priv; void *priv;