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authorFelipe Balbi <balbi@ti.com>2014-04-23 09:58:26 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-30 20:09:44 -0700
commita22d29e6e5757b1daed7d0b409a815eb33f66e4e (patch)
treeddf50395a27740c73be3ac5acda499ab6ef439e5 /drivers/bluetooth
parent1a73877050e0cc7638b42901762fa411abda2512 (diff)
bluetooth: hci_ldisc: fix deadlock condition
commit da64c27d3c93ee9f89956b9de86c4127eb244494 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/bluetooth')
-rw-r--r--drivers/bluetooth/hci_ldisc.c24
-rw-r--r--drivers/bluetooth/hci_uart.h1
2 files changed, 20 insertions, 5 deletions
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index bc68a440d432..c4d2f0e48685 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -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 @@ restart:
goto restart;
clear_bit(HCI_UART_SENDING, &hu->tx_state);
- return 0;
}
static void hci_uart_init_work(struct work_struct *work)
@@ -289,6 +300,7 @@ 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);
@@ -326,6 +338,8 @@ 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))
diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h
index fffa61ff5cb1..12df101ca942 100644
--- a/drivers/bluetooth/hci_uart.h
+++ b/drivers/bluetooth/hci_uart.h
@@ -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;