From e98348e0cb52dbb48d505b54646180a1455d630c Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 9 Sep 2014 16:16:05 -0700 Subject: [PATCH] staging: comedi: usbdux: prevent "empty acquisition" async commands This driver currently allows a cmd->stop_src == TRIG_COUNT with a cmd->stop_arg of 0 for both the analog input and output async commands. The (*do_cmd) for both subdevices sets up and starts the command without handling the "empty acquisition". This results in the interrupt functions trying to transfer 0 data samples. Validate that the cmd->stop_arg is >= 1 in the (*do_cmdtest) to prevent the "empty acquisition". Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/usbdux.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/drivers/staging/comedi/drivers/usbdux.c b/drivers/staging/comedi/drivers/usbdux.c index 8eb2742e6fef..5adbfedf780f 100644 --- a/drivers/staging/comedi/drivers/usbdux.c +++ b/drivers/staging/comedi/drivers/usbdux.c @@ -623,12 +623,10 @@ static int usbdux_ai_cmdtest(struct comedi_device *dev, err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len); - if (cmd->stop_src == TRIG_COUNT) { - /* any count is allowed */ - } else { - /* TRIG_NONE */ + if (cmd->stop_src == TRIG_COUNT) + err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1); + else /* TRIG_NONE */ err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0); - } if (err) return 3; @@ -1003,12 +1001,10 @@ static int usbdux_ao_cmdtest(struct comedi_device *dev, err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len); - if (cmd->stop_src == TRIG_COUNT) { - /* any count is allowed */ - } else { - /* TRIG_NONE */ + if (cmd->stop_src == TRIG_COUNT) + err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1); + else /* TRIG_NONE */ err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0); - } if (err) return 3; -- 2.20.1