Commit 8c602c49 authored Sep 09, 2014 by H Hartley Sweeten Committed by Greg Kroah-Hartman Sep 11, 2014

staging: comedi: rtd520: prevent "empty acquisition" async command



This driver currently allows a cmd->stop_src == TRIG_COUNT with a cmd->stop_arg
of 0. The (*do_cmd) then sets up and starts the command without handling the "empty
acquisition". This results in the interrupt function 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 <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 1e2e39ef

drivers/staging/comedi/drivers/rtd520.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -874,12 +874,10 @@ static int rtd_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) {
		/* TODO check for rounding error due to counter wrap */
		} 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;