This is a note to let you know that I've just added the patch titled serial: pch: Fix PCI device refcount leak in pch_request_dma() to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: serial-pch-fix-pci-device-refcount-leak-in-pch_reque.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit c17ad747615436a6115b7c613c66b25e9dd42d97 Author: Xiongfeng Wang <wangxiongfeng2@xxxxxxxxxx> Date: Tue Nov 22 19:45:59 2022 +0800 serial: pch: Fix PCI device refcount leak in pch_request_dma() [ Upstream commit 8be3a7bf773700534a6e8f87f6ed2ed111254be5 ] As comment of pci_get_slot() says, it returns a pci_device with its refcount increased. The caller must decrement the reference count by calling pci_dev_put(). Since 'dma_dev' is only used to filter the channel in filter(), we can call pci_dev_put() before exiting from pch_request_dma(). Add the missing pci_dev_put() for the normal and error path. Fixes: 3c6a483275f4 ("Serial: EG20T: add PCH_UART driver") Signed-off-by: Xiongfeng Wang <wangxiongfeng2@xxxxxxxxxx> Link: https://lore.kernel.org/r/20221122114559.27692-1-wangxiongfeng2@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index 77f18445bb98..a8b6759140dd 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -718,6 +718,7 @@ 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; } priv->chan_tx = chan; @@ -734,6 +735,7 @@ static void pch_request_dma(struct uart_port *port) __func__); dma_release_channel(priv->chan_tx); priv->chan_tx = NULL; + pci_dev_put(dma_dev); return; } @@ -741,6 +743,8 @@ static void pch_request_dma(struct uart_port *port) priv->rx_buf_virt = dma_alloc_coherent(port->dev, port->fifosize, &priv->rx_buf_dma, GFP_KERNEL); priv->chan_rx = chan; + + pci_dev_put(dma_dev); } static void pch_dma_rx_complete(void *arg)