linux-kernel - [PATCH v2][next] counter: Add default statement to switch() in quad8_function

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Date:   Mon, 20 Sep 2021 11:37:37 -0600
From:   Tim Gardner <tim.gardner@...onical.com>
To:     linux-iio@...r.kernel.org
Cc:     tim.gardner@...onical.com,
        William Breathitt Gray <vilhelm.gray@...il.com>,
        Syed Nayyar Waris <syednwaris@...il.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2][next] counter: Add default statement to switch() in quad8_function_read()

v2: Add the correct Cc's

Coverity complains of a possible use of an uninitialized variable
in quad8_action_read().

CID 119643 (#1 of 1): Uninitialized scalar variable (UNINIT)
4. uninit_use: Using uninitialized value function.
346        switch (function) {

The call to quad8_function_read() could theoretically return without
assigning a value to '*function', thus causing the use of an
ininitialized variable 'function' in quad8_action_read().

Fix this by adding a default statement to the switch in
quad8_function_read() and returning an error.

Cc: William Breathitt Gray <vilhelm.gray@...il.com>
Cc: Syed Nayyar Waris <syednwaris@...il.com>
Cc: linux-iio@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Tim Gardner <tim.gardner@...onical.com>
---
 drivers/counter/104-quad-8.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index c587f295d720..3a69d35b82ea 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -215,6 +215,8 @@ static int quad8_function_read(struct counter_device *counter,
 		case 2:
 			*function = COUNTER_FUNCTION_QUADRATURE_X4;
 			break;
+		default:
+			return -1;
 		}
 	else
 		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
-- 
2.33.0