From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kangjie Lu Subject: [PATCH v2] tty: atmel_serial: fix a NULL pointer dereference Date: Fri, 15 Mar 2019 02:27:09 -0500 Message-ID: <20190315072709.22811-1-kjlu@umn.edu> References: Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: kjlu@umn.edu Cc: Richard Genoud , Greg Kroah-Hartman , Jiri Slaby , Nicolas Ferre , Alexandre Belloni , Ludovic Desroches , linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: linux-serial@vger.kernel.org Fixes: 34df42f59a60 ("serial: at91: add rx dma support") In case dmaengine_prep_dma_cyclic fails, the fix returns a proper error code to avoid NULL pointer dereference. Signed-off-by: Kangjie Lu --- V2: simplified the patch as suggested by Richard Genoud --- 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 05147fe24343..41b728d223d1 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1288,6 +1288,10 @@ 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; -- 2.17.1