Re: [PATCH v2] serial: pch_uart: potential dereference of null pointer
From: Greg KH <gregkh@linuxfoundation.org>
Date: 2021-12-16 13:15:19
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On Thu, Dec 16, 2021 at 08:51:21PM +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/")That is not the commit that caused the problem :(
quoted hunk ↗ jump to hunk
Signed-off-by: Jiasheng Jiang <redacted> --- Changelog: v1 -> v2 *Change 1. Add the dev_err when dma_alloc_coherent failed. --- drivers/tty/serial/pch_uart.c | 8 ++++++++ 1 file changed, 8 insertions(+)diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index f0351e6f0ef6..d19ed7da24fa 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c@@ -745,6 +745,14 @@ 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) { + dev_err(priv->port.dev, "%s:dma_alloc_coherent FAILS(Rx)\n", + __func__); + dma_release_channel(priv->chan_tx); + priv->chan_tx = NULL; + return;
You seemed to have ignored my previous review comments on this change for some reason :( This is not correct. greg k-h