From: Ronald Tschalär ronald@innovation.ch
[ Upstream commit 0338b1b393ec7910898e8f7b25b3bf31a7282e16 ]
The following race condition still existed:
P1 P2 cancel_work_sync() hci_uart_tx_wakeup() hci_uart_write_work() hci_uart_dequeue() clear_bit(HCI_UART_PROTO_READY) hci_unregister_dev(hdev) hci_free_dev(hdev) hu->proto->close(hu) kfree(hu) access to hdev and hu
Cancelling the work after clearing the HCI_UART_PROTO_READY bit avoids this as any hci_uart_tx_wakeup() issued after the flag is cleared will detect that and not schedule further work.
Signed-off-by: Ronald Tschalär ronald@innovation.ch Reviewed-by: Lukas Wunner lukas@wunner.de Signed-off-by: Marcel Holtmann marcel@holtmann.org Signed-off-by: Sasha Levin alexander.levin@verizon.com --- drivers/bluetooth/hci_ldisc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index a746627e784e..6e2403805784 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -510,13 +510,13 @@ static void hci_uart_tty_close(struct tty_struct *tty) if (hdev) hci_uart_close(hdev);
- cancel_work_sync(&hu->write_work); - if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) { write_lock_irqsave(&hu->proto_lock, flags); clear_bit(HCI_UART_PROTO_READY, &hu->flags); write_unlock_irqrestore(&hu->proto_lock, flags);
+ cancel_work_sync(&hu->write_work); + if (hdev) { if (test_bit(HCI_UART_REGISTERED, &hu->flags)) hci_unregister_dev(hdev);