* [PATCH] serial: pch_uart: potential dereference of null pointer
@ 2021-12-16 9:44 Jiasheng Jiang
2021-12-16 10:18 ` Greg KH
0 siblings, 1 reply; 2+ messages in thread
From: Jiasheng Jiang @ 2021-12-16 9:44 UTC (permalink / raw)
To: gregkh, jirislaby; +Cc: linux-serial, linux-kernel, Jiasheng Jiang
The return value of dma_alloc_coherent() needs to be checked.
To avoid dereference of null pointer in case of the failure of alloc.
Fixes: ab4382d27412 ("tty: move drivers/serial/ to drivers/tty/serial/")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
---
drivers/tty/serial/pch_uart.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index f0351e6f0ef6..2ee1c4d6f177 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -745,6 +745,12 @@ static void pch_request_dma(struct uart_port *port)
/* Get Consistent memory for DMA */
priv->rx_buf_virt = dma_alloc_coherent(port->dev, port->fifosize,
&priv->rx_buf_dma, GFP_KERNEL);
+ if (!priv->rx_buf_virt) {
+ dma_release_channel(priv->chan_tx);
+ priv->chan_tx = NULL;
+ return;
+ }
+
priv->chan_rx = chan;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] serial: pch_uart: potential dereference of null pointer
2021-12-16 9:44 [PATCH] serial: pch_uart: potential dereference of null pointer Jiasheng Jiang
@ 2021-12-16 10:18 ` Greg KH
0 siblings, 0 replies; 2+ messages in thread
From: Greg KH @ 2021-12-16 10:18 UTC (permalink / raw)
To: Jiasheng Jiang; +Cc: jirislaby, linux-serial, linux-kernel
On Thu, Dec 16, 2021 at 05:44:08PM +0800, Jiasheng Jiang wrote:
> The return value of dma_alloc_coherent() needs to be checked.
> To avoid dereference of null pointer in case of the failure of alloc.
>
> Fixes: ab4382d27412 ("tty: move drivers/serial/ to drivers/tty/serial/")
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
> ---
> drivers/tty/serial/pch_uart.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
> index f0351e6f0ef6..2ee1c4d6f177 100644
> --- a/drivers/tty/serial/pch_uart.c
> +++ b/drivers/tty/serial/pch_uart.c
> @@ -745,6 +745,12 @@ static void pch_request_dma(struct uart_port *port)
> /* Get Consistent memory for DMA */
> priv->rx_buf_virt = dma_alloc_coherent(port->dev, port->fifosize,
> &priv->rx_buf_dma, GFP_KERNEL);
> + if (!priv->rx_buf_virt) {
> + dma_release_channel(priv->chan_tx);
> + priv->chan_tx = NULL;
> + return;
You are not returning an error, what happens when this buffer is later
attempted to be used?
How did you test this change?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-12-16 9:44 [PATCH] serial: pch_uart: potential dereference of null pointer Jiasheng Jiang
2021-12-16 10:18 ` Greg KH
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