| Message ID | 20200821180106.21048-1-sonnysasaka@chromium.org (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [BlueZ,v2] device: Fix race condition between device connection and disconnection | expand |
Hi Sonny, On Fri, Aug 21, 2020 at 11:04 AM Sonny Sasaka <sonnysasaka@chromium.org> wrote: > > When Connect() is called and waiting for return, dev_disconnected may be > called due to MGMT_EV_DEVICE_DISCONNECTED event from kernel. In that > case reply to client that the connection failed otherwise the dbus > method will timeout because bluetoothd never replies. > > Tested with simulation of a lot of Connect() to bluetooth devices and > check that error is returned from bluetoothd rather than dbus timeout > when this race condition happens. > > Reviewed-by: Miao-chen Chou <mcchou@chromium.org> > > --- > src/device.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/src/device.c b/src/device.c > index 7b7808405..f59b6c1d0 100644 > --- a/src/device.c > +++ b/src/device.c > @@ -3006,6 +3006,7 @@ void device_add_connection(struct btd_device *dev, uint8_t bdaddr_type) > void device_remove_connection(struct btd_device *device, uint8_t bdaddr_type) > { > struct bearer_state *state = get_state(device, bdaddr_type); > + DBusMessage *reply; > > if (!state->connected) > return; > @@ -3020,6 +3021,18 @@ void device_remove_connection(struct btd_device *device, uint8_t bdaddr_type) > device->disconn_timer = 0; > } > > + /* This could be executed while the client is waiting for Connect() but > + * att_connect_cb has not been invoked. > + * In that case reply the client that the connection failed. > + */ > + if (device->connect) { > + DBG("connection removed while Connect() is waiting reply"); > + reply = btd_error_failed(device->connect, "Disconnected early"); > + g_dbus_send_message(dbus_conn, reply); > + dbus_message_unref(device->connect); > + device->connect = NULL; > + } > + > while (device->disconnects) { > DBusMessage *msg = device->disconnects->data; > > -- > 2.26.2 > Applied, thanks.
diff --git a/src/device.c b/src/device.c index 7b7808405..f59b6c1d0 100644 --- a/src/device.c +++ b/src/device.c @@ -3006,6 +3006,7 @@ void device_add_connection(struct btd_device *dev, uint8_t bdaddr_type) void device_remove_connection(struct btd_device *device, uint8_t bdaddr_type) { struct bearer_state *state = get_state(device, bdaddr_type); + DBusMessage *reply; if (!state->connected) return; @@ -3020,6 +3021,18 @@ void device_remove_connection(struct btd_device *device, uint8_t bdaddr_type) device->disconn_timer = 0; } + /* This could be executed while the client is waiting for Connect() but + * att_connect_cb has not been invoked. + * In that case reply the client that the connection failed. + */ + if (device->connect) { + DBG("connection removed while Connect() is waiting reply"); + reply = btd_error_failed(device->connect, "Disconnected early"); + g_dbus_send_message(dbus_conn, reply); + dbus_message_unref(device->connect); + device->connect = NULL; + } + while (device->disconnects) { DBusMessage *msg = device->disconnects->data;
When Connect() is called and waiting for return, dev_disconnected may be called due to MGMT_EV_DEVICE_DISCONNECTED event from kernel. In that case reply to client that the connection failed otherwise the dbus method will timeout because bluetoothd never replies. Tested with simulation of a lot of Connect() to bluetooth devices and check that error is returned from bluetoothd rather than dbus timeout when this race condition happens. Reviewed-by: Miao-chen Chou <mcchou@chromium.org> --- src/device.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)