From c85be041065c0be8bc48eda4c45e0319caf1d0e5 Mon Sep 17 00:00:00 2001
From: Kangjie Lu <kjlu@umn.edu>
Date: Fri, 15 Mar 2019 12:16:06 -0500
Subject: [PATCH] tty: atmel_serial: fix a potential NULL pointer dereference
Git-commit: c85be041065c0be8bc48eda4c45e0319caf1d0e5
Patch-mainline: v5.1-rc3
References: bsc#1051510
In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
error code to avoid NULL pointer dereference.
Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Fixes: 34df42f59a60 ("serial: at91: add rx dma support")
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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;
--
2.16.4