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Commit e98348e0 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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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: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 32f9ff70

drivers/staging/comedi/drivers/usbdux.c

+6 −10
Original line number Diff line number Diff line
@@ -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;