[lvc-project] [PATCH] comedi: adl_pci9111: Fix possible division by zero in pci9111_ai_do_cmd_test()

[Aleksandr Mishin]

Division by zero is possible in pci9111_ai_do_cmd_test() in case of scan
begin trigger source is TRIG_TIMER and either 'chanlist_len' or
'convert_arg' is zero.

Add zero value check to prevent division by zero.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: f1c51faabc4d ("staging: comedi: adl_pci9111: tidy up (*do_cmdtest) Step 4")
Signed-off-by: Aleksandr Mishin <amishin at t-argos.ru>
---
 drivers/comedi/drivers/adl_pci9111.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/comedi/drivers/adl_pci9111.c b/drivers/comedi/drivers/adl_pci9111.c
index 086d93f40cb9..ec1fb570b98c 100644
--- a/drivers/comedi/drivers/adl_pci9111.c
+++ b/drivers/comedi/drivers/adl_pci9111.c
@@ -312,6 +312,8 @@ static int pci9111_ai_do_cmd_test(struct comedi_device *dev,
 	 */
 	if (cmd->scan_begin_src == TRIG_TIMER) {
 		arg = cmd->chanlist_len * cmd->convert_arg;
+		if (!arg)
+			return 4;
 
 		if (arg < cmd->scan_begin_arg)
 			arg *= (cmd->scan_begin_arg / arg);
-- 
2.30.2