From fe186fdd1a45b5e33dd85f7bf63e70049f99b230 Mon Sep 17 00:00:00 2001 From: Kangjie Lu Date: Fri, 15 Mar 2019 12:16:06 -0500 Subject: [PATCH] tty: atmel_serial: fix a potential NULL pointer dereference commit c85be041065c0be8bc48eda4c45e0319caf1d0e5 upstream. In case dmaengine_prep_dma_cyclic fails, the fix returns a proper error code to avoid NULL pointer dereference. Signed-off-by: Kangjie Lu Fixes: 34df42f59a60 ("serial: at91: add rx dma support") Acked-by: Richard Genoud Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/atmel_serial.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 5a341b1c65c3..d8e1945cb627 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1166,6 +1166,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port) sg_dma_len(&atmel_port->sg_rx)/2, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT); + if (!desc) { + dev_err(port->dev, "Preparing DMA cyclic failed\n"); + goto chan_err; + } desc->callback = atmel_complete_rx_dma; desc->callback_param = port; atmel_port->desc_rx = desc; -- 2.34.1