serial: Fix potential null-ptr-deref in mlb_usio_probe()

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>

diff --git a/drivers/tty/serial/milbeaut_usio.c b/drivers/tty/serial/milbeaut_usio.c
index 059bea18dbab569a610cb96a1f153a01ca9d362c..4e47dca2c4ed9ce650a21f8345aa445178a1c6ee 100644 (file)
--- 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;