From: Claire Chang tientzu@chromium.org
[ Upstream commit afe0b1c86458f121b085271e4f3034017a90d4a3 ]
In hci_uart_write_work, there is a loop/goto checking the value of HCI_UART_TX_WAKEUP. If HCI_UART_TX_WAKEUP is set again, it keeps trying hci_uart_dequeue; otherwise, it clears HCI_UART_SENDING and returns.
In hci_uart_tx_wakeup, if HCI_UART_SENDING is already set, it sets HCI_UART_TX_WAKEUP, skips schedule_work and assumes the running/pending hci_uart_write_work worker will do hci_uart_dequeue properly.
However, if the HCI_UART_SENDING check in hci_uart_tx_wakeup is done after the loop breaks, but before HCI_UART_SENDING is cleared in hci_uart_write_work, the schedule_work is skipped incorrectly.
Fix this race by changing the order of HCI_UART_SENDING and HCI_UART_TX_WAKEUP modification.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Fixes: 82f5169bf3d3 ("Bluetooth: hci_uart: add serdev driver support library") Signed-off-by: Claire Chang tientzu@chromium.org Signed-off-by: Marcel Holtmann marcel@holtmann.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/bluetooth/hci_ldisc.c | 7 +++---- drivers/bluetooth/hci_serdev.c | 4 ++-- 2 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index f83d67eafc9f0..8be4d807d1370 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -127,10 +127,9 @@ int hci_uart_tx_wakeup(struct hci_uart *hu) if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) goto no_schedule;
- 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); + if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) goto no_schedule; - }
BT_DBG("");
@@ -174,10 +173,10 @@ restart: kfree_skb(skb); }
+ clear_bit(HCI_UART_SENDING, &hu->tx_state); if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state)) goto restart;
- clear_bit(HCI_UART_SENDING, &hu->tx_state); wake_up_bit(&hu->tx_state, HCI_UART_SENDING); }
diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c index 5b9aa73ff2b7f..1b4ad231e6ed3 100644 --- a/drivers/bluetooth/hci_serdev.c +++ b/drivers/bluetooth/hci_serdev.c @@ -85,9 +85,9 @@ static void hci_uart_write_work(struct work_struct *work) hci_uart_tx_complete(hu, hci_skb_pkt_type(skb)); kfree_skb(skb); } - } while (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state));
- clear_bit(HCI_UART_SENDING, &hu->tx_state); + clear_bit(HCI_UART_SENDING, &hu->tx_state); + } while (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state)); }
/* ------- Interface to HCI layer ------ */