[PATCH 6.6 231/356] serial: Fix potential null-ptr-deref in mlb_usio_probe()

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

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

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

From: Henry Martin <bsdhenrymartin@gmail.com>

[ Upstream commit 86bcae88c9209e334b2f8c252f4cc66beb261886 ]

devm_ioremap() can return NULL on error. Currently, mlb_usio_probe()
does not check for this case, which could result in a NULL pointer
dereference.

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

Fixes: ba44dc043004 ("serial: Add Milbeaut serial control")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
Link: https://lore.kernel.org/r/20250403070339.64990-1-bsdhenrymartin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 70a910085e937..9de3883a4e0b0 100644
--- a/drivers/tty/serial/milbeaut_usio.c
+++ b/drivers/tty/serial/milbeaut_usio.c
@@ -522,7 +522,10 @@ 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;
 
-- 
2.39.5