Hi Luiz Augusto von Dentz and all experts Sorry for I send out a duplicate patch again. Just ignore this duplicate patch, please. Thanks! Joey Lee On Sat, Jul 15, 2023 at 12:08:54AM +0800, Lee, Chun-Yi wrote: > This patch adds code to check HCI_UART_PROTO_READY flag before > accessing hci_uart->proto. It fixs the race condition in > hci_uart_tty_ioctl() between HCIUARTSETPROTO and HCIUARTGETPROTO. > This issue bug found by Yu Hao and Weiteng Chen: > > BUG: general protection fault in hci_uart_tty_ioctl [1] > > The information of C reproducer can also reference the link [2] > > Reported-by: Yu Hao <yhao016@xxxxxxx> > Closes: https://lore.kernel.org/all/CA+UBctC3p49aTgzbVgkSZ2+TQcqq4fPDO7yZitFT5uBPDeCO2g@xxxxxxxxxxxxxx/ [1] > Reported-by: Weiteng Chen <wchen130@xxxxxxx> > Closes: https://lore.kernel.org/lkml/CA+UBctDPEvHdkHMwD340=n02rh+jNRJNNQ5LBZNA+Wm4Keh2ow@xxxxxxxxxxxxxx/T/ [2] > Signed-off-by: "Lee, Chun-Yi" <jlee@xxxxxxxx> > --- > drivers/bluetooth/hci_ldisc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c > index efdda2c3fce8..a76eb98c0047 100644 > --- a/drivers/bluetooth/hci_ldisc.c > +++ b/drivers/bluetooth/hci_ldisc.c > @@ -770,7 +770,8 @@ static int hci_uart_tty_ioctl(struct tty_struct *tty, unsigned int cmd, > break; > > case HCIUARTGETPROTO: > - if (test_bit(HCI_UART_PROTO_SET, &hu->flags)) > + if (test_bit(HCI_UART_PROTO_SET, &hu->flags) && > + test_bit(HCI_UART_PROTO_READY, &hu->flags)) > err = hu->proto->id; > else > err = -EUNATCH; > -- > 2.35.3
