4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kangjie Lu <kjlu@xxxxxxx>
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 <kjlu@xxxxxxx>
Fixes: 34df42f59a60 ("serial: at91: add rx dma support")
Acked-by: Richard Genoud <richard.genoud@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/atmel_serial.c | 4 ++++
1 file changed, 4 insertions(+)
--- 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 u
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;
