From: Lanqing Liu <liuhhome@xxxxxxxxx> commit efc176929a3505a30c3993ddd393b40893649bd2 upstream. We should validate if the 'sup' is NULL or not before freeing DMA memory, to fix below warning. "drivers/tty/serial/sprd_serial.c:1141 sprd_remove() error: we previously assumed 'sup' could be null (see line 1132)" Fixes: f4487db58eb7 ("serial: sprd: Add DMA mode support") Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Lanqing Liu <liuhhome@xxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/e2bd92691538e95b04a2c2a728f3292e1617018f.1584325957.git.liuhhome@xxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/sprd_serial.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/tty/serial/sprd_serial.c +++ b/drivers/tty/serial/sprd_serial.c @@ -1132,14 +1132,13 @@ static int sprd_remove(struct platform_d if (sup) { uart_remove_one_port(&sprd_uart_driver, &sup->port); sprd_port[sup->port.line] = NULL; + sprd_rx_free_buf(sup); sprd_ports_num--; } if (!sprd_ports_num) uart_unregister_driver(&sprd_uart_driver); - sprd_rx_free_buf(sup); - return 0; }