Patchwork tty: atmel_serial: fix a NULL pointer dereference

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Submitter Kangjie Lu
Date March 15, 2019, 5:16 p.m.
Message ID <20190315171606.6282-1-kjlu@umn.edu>
Download mbox | patch
Permalink /patch/749867/
State New
Headers show

Comments

Kangjie Lu - March 15, 2019, 5:16 p.m.
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")

---
V2: simplified the patch as suggested by
Richard Genoud <richard.genoud@gmail.com>
---
 drivers/tty/serial/atmel_serial.c | 4 ++++
 1 file changed, 4 insertions(+)
Richard Genoud - March 18, 2019, 7:28 a.m.
Le 15/03/2019 à 18:16, Kangjie Lu a écrit :
> 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>

> 
> ---
> V2: simplified the patch as suggested by
> Richard Genoud <richard.genoud@gmail.com>
> ---
>  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;
> 

Thanks !

Richard

Patch

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;