Hi Chan-yeol, On Fri, Mar 22, 2013, Chan-yeol Park wrote: > This patch adds check HCI_UART_REGISTERED before reading uart packet because > BT uart data could be read before hci_uart is registered. > > Backtrace: > [<c05f27ec>] (hci_recv_stream_fragment+0x0/0x74) from [<c04126f4>] (h4_recv+0x18/0x40) > r7:eb1d4d1c r6:eb7683b0 r5:eae8e800 r4:0000000c > [<c04126dc>] (h4_recv+0x0/0x40) from [<c0411870>] (hci_uart_tty_receive+0x6c/0x94) > r5:eae8e800 r4:eb768380 > [<c0411804>] (hci_uart_tty_receive+0x0/0x94) from [<c027be88>] (flush_to_ldisc+0x16c/0x17c) > r6:eae8e8d8 r5:eae8e800 r4:eae8e8c8 > [<c027bd1c>] (flush_to_ldisc+0x0/0x17c) from [<c0050ae8>] (process_one_work+0x144/0x4d4) > [<c00509a4>] (process_one_work+0x0/0x4d4) from [<c0051208>] (worker_thread+0x180/0x370) > [<c0051088>] (worker_thread+0x0/0x370) from [<c005617c>] (kthread+0x90/0x9c) > [<c00560ec>] (kthread+0x0/0x9c) from [<c003a3a0>] (do_exit+0x0/0x7ec) > > Signed-off-by: Chan-yeol Park <chanyeol.park@xxxxxxxxxxx> > --- > drivers/bluetooth/hci_ldisc.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c > index ed0fade..476a307 100644 > --- a/drivers/bluetooth/hci_ldisc.c > +++ b/drivers/bluetooth/hci_ldisc.c > @@ -386,6 +386,9 @@ static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, char *f > if (!test_bit(HCI_UART_PROTO_SET, &hu->flags)) > return; > > + if (!test_bit(HCI_UART_REGISTERED, &hu->flags)) > + return; > + > spin_lock(&hu->rx_lock); > hu->proto->recv(hu, (void *) data, count); > hu->hdev->stat.byte_rx += count; Wouldn't this break HCI drivers that have a transport specific init sequence, like H5, i.e. those that rely on transmitting data before the HCI device is registered? I think your commit message should more clearly explain how you manage to reproduce this condition. It seems to me like data arrives when inside the hci_uart_tty_ioctl function after calling test_and_set_bit for HCI_UART_PROTO_SET but before the hci_uart_set_proto function has returned (and thus called hci_register_dev in the case of H4). Is that correct? Johan -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
