[PATCH v2] serial: Fix null-ptr-deref in mlb_usio_probe()

[Henry Martin <bsdhenrymartin@gmail.com>]

devm_ioremap() returns NULL on error. Currently, mlb_usio_probe() does
not check for this case, which results in a NULL pointer dereference.

Add NULL check after devm_ioremap() to prevent this issue.

Cc: stable@vger.kernel.org
Fixes: ba44dc043004 ("serial: Add Milbeaut serial control")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
---
V1 -> V2: Add cc: stable line.

 drivers/tty/serial/milbeaut_usio.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/milbeaut_usio.c b/drivers/tty/serial/milbeaut_usio.c
index 059bea18dbab..4e47dca2c4ed 100644
--- a/drivers/tty/serial/milbeaut_usio.c
+++ b/drivers/tty/serial/milbeaut_usio.c
@@ -523,7 +523,10 @@ static int mlb_usio_probe(struct platform_device *pdev)
 	}
 	port->membase = devm_ioremap(&pdev->dev, res->start,
 				resource_size(res));
-
+	if (!port->membase) {
+		ret = -ENOMEM;
+		goto failed;
+	}
 	ret = platform_get_irq_byname(pdev, "rx");
 	mlb_usio_irq[index][RX] = ret;
 
-- 
2.34.1