[PATCH] serial: 8250_lpss: Fix missing check for return value of pci_get_slot()

[Chenyuan Mi]

The pci_get_slot() function may return NULL, which may
cause null pointer deference, and most other callsites of
pci_get_slot() do Null check. Add Null check for return
value of pci_get_slot().

Found by our static analysis tool.

Signed-off-by: Chenyuan Mi <cymi20@xxxxxxxxxxxx>
---
 drivers/tty/serial/8250/8250_lpss.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
index 0e43bdfb7459..05af5865ee1b 100644
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -137,6 +137,8 @@ static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
 	}
 
 	dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(PCI_SLOT(pdev->devfn), 0));
+	if (!dma_dev)
+		return -ENODEV;
 
 	param->dma_dev = &dma_dev->dev;
 	param->m_master = 0;
-- 
2.17.1