[PATCH 4.9 26/33] serial: sccnxp: Fix error handling in sccnxp_probe()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexey Khoroshilov <khoroshilov@ispras.ru>

commit c91261437985d481c472639d4397931d77f5d4e9 upstream.

sccnxp_probe() returns result of regulator_disable() that may lead
to returning zero, while device is not properly initialized.
Also the driver enables clocks, but it does not disable it.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/tty/serial/sccnxp.c |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

--- a/drivers/tty/serial/sccnxp.c
+++ b/drivers/tty/serial/sccnxp.c
@@ -889,7 +889,16 @@ static int sccnxp_probe(struct platform_
 			goto err_out;
 		uartclk = 0;
 	} else {
-		clk_prepare_enable(clk);
+		ret = clk_prepare_enable(clk);
+		if (ret)
+			goto err_out;
+
+		ret = devm_add_action_or_reset(&pdev->dev,
+				(void(*)(void *))clk_disable_unprepare,
+				clk);
+		if (ret)
+			goto err_out;
+
 		uartclk = clk_get_rate(clk);
 	}
 
@@ -988,7 +997,7 @@ static int sccnxp_probe(struct platform_
 	uart_unregister_driver(&s->uart);
 err_out:
 	if (!IS_ERR(s->regulator))
-		return regulator_disable(s->regulator);
+		regulator_disable(s->regulator);
 
 	return ret;
 }