releases/4.14.110/tty-atmel_serial-fix-a-potential-null-pointer-dereference.patch

   1 From c85be041065c0be8bc48eda4c45e0319caf1d0e5 Mon Sep 17 00:00:00 2001
   2 From: Kangjie Lu <kjlu@umn.edu>
   3 Date: Fri, 15 Mar 2019 12:16:06 -0500
   4 Subject: tty: atmel_serial: fix a potential NULL pointer dereference
   5
   6 From: Kangjie Lu <kjlu@umn.edu>
   7
   8 commit c85be041065c0be8bc48eda4c45e0319caf1d0e5 upstream.
   9
  10 In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
  11 error code to avoid NULL pointer dereference.
  12
  13 Signed-off-by: Kangjie Lu <kjlu@umn.edu>
  14 Fixes: 34df42f59a60 ("serial: at91: add rx dma support")
  15 Acked-by: Richard Genoud <richard.genoud@gmail.com>
  16 Cc: stable <stable@vger.kernel.org>
  17 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  18
  19 ---
  20  drivers/tty/serial/atmel_serial.c |    4 ++++
  21  1 file changed, 4 insertions(+)
  22
  23 --- a/drivers/tty/serial/atmel_serial.c
  24 +++ b/drivers/tty/serial/atmel_serial.c
  25 @@ -1163,6 +1163,10 @@ static int atmel_prepare_rx_dma(struct u
  26                                          sg_dma_len(&atmel_port->sg_rx)/2,
  27                                          DMA_DEV_TO_MEM,
  28                                          DMA_PREP_INTERRUPT);
  29 +       if (!desc) {
  30 +               dev_err(port->dev, "Preparing DMA cyclic failed\n");
  31 +               goto chan_err;
  32 +       }
  33         desc->callback = atmel_complete_rx_dma;
  34         desc->callback_param = port;
  35         atmel_port->desc_rx = desc;