tty: serial: pch_uart: add check for dma_alloc_coherent()

Add a check for dma_alloc_coherent() failure to prevent a potential
NULL pointer dereference in dma_handle_rx(). Properly release DMA
channels and the PCI device reference using a goto ladder if the
allocation fails.

Fixes: 3c6a483275f4 ("Serial: EG20T: add PCH_UART driver")
Cc: stable <stable@kernel.org>
Signed-off-by: Zhaoyang Yu <2426767509@qq.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/tencent_E328416B7CFD436F6029F2DF02AD7ED89C08@qq.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 6729d8e83c3c542f513262d5772af5bed5dae134..ba1fcd663fe22856f347955cb346803e92953ece 100644 (file)
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -689,8 +689,7 @@ static void pch_request_dma(struct uart_port *port)
        if (!chan) {
                dev_err(priv->port.dev, "%s:dma_request_channel FAILS(Tx)\n",
                        __func__);
-               pci_dev_put(dma_dev);
-               return;
+               goto err_pci_get;
        }
        priv->chan_tx = chan;
 
@@ -704,18 +703,26 @@ static void pch_request_dma(struct uart_port *port)
        if (!chan) {
                dev_err(priv->port.dev, "%s:dma_request_channel FAILS(Rx)\n",
                        __func__);
-               dma_release_channel(priv->chan_tx);
-               priv->chan_tx = NULL;
-               pci_dev_put(dma_dev);
-               return;
+               goto err_req_tx;
        }
 
        /* 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)
+               goto err_req_rx;
        priv->chan_rx = chan;
 
        pci_dev_put(dma_dev);
+       return;
+
+err_req_rx:
+       dma_release_channel(chan);
+err_req_tx:
+       dma_release_channel(priv->chan_tx);
+       priv->chan_tx = NULL;
+err_pci_get:
+       pci_dev_put(dma_dev);
 }
 
 static void pch_dma_rx_complete(void *arg)