From 6fe472c1bbbe238e91141f7cabc1226e96a60d43 Mon Sep 17 00:00:00 2001 From: Zhaoyang Yu <2426767509@qq.com> Date: Thu, 9 Apr 2026 13:41:58 +0800 Subject: [PATCH] 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 Signed-off-by: Zhaoyang Yu <2426767509@qq.com> Reviewed-by: Andy Shevchenko Link: https://patch.msgid.link/tencent_E328416B7CFD436F6029F2DF02AD7ED89C08@qq.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/pch_uart.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index 6729d8e83c3c..ba1fcd663fe2 100644 --- 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)