Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754697AbdDFIju (ORCPT ); Thu, 6 Apr 2017 04:39:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:50378 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754291AbdDFIjh (ORCPT ); Thu, 6 Apr 2017 04:39:37 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nicolas Ferre , Richard Genoud Subject: [PATCH 4.4 11/26] tty/serial: atmel: fix race condition (TX+DMA) Date: Thu, 6 Apr 2017 10:38:33 +0200 Message-Id: <20170406083604.893574194@linuxfoundation.org> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170406083604.362636628@linuxfoundation.org> References: <20170406083604.362636628@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1109 Lines: 37 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Richard Genoud commit 31ca2c63fdc0aee725cbd4f207c1256f5deaabde upstream. If uart_flush_buffer() is called between atmel_tx_dma() and atmel_complete_tx_dma(), the circular buffer has been cleared, but not atmel_port->tx_len. That leads to a circular buffer overflow (dumping (UART_XMIT_SIZE - atmel_port->tx_len) bytes). Tested-by: Nicolas Ferre Signed-off-by: Richard Genoud Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/atmel_serial.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1987,6 +1987,11 @@ static void atmel_flush_buffer(struct ua atmel_uart_writel(port, ATMEL_PDC_TCR, 0); atmel_port->pdc_tx.ofs = 0; } + /* + * in uart_flush_buffer(), the xmit circular buffer has just + * been cleared, so we have to reset tx_len accordingly. + */ + atmel_port->tx_len = 0; } /*