Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754900AbdDJPfm (ORCPT ); Mon, 10 Apr 2017 11:35:42 -0400 Received: from mx2.suse.de ([195.135.220.15]:38054 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754839AbdDJPfE (ORCPT ); Mon, 10 Apr 2017 11:35:04 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Richard Genoud , Greg Kroah-Hartman , Jiri Slaby Subject: [PATCH 3.12 142/142] tty/serial: atmel: fix race condition (TX+DMA) Date: Mon, 10 Apr 2017 17:33:43 +0200 Message-Id: <83581c098fcb07e8c97d49508f2d99c5b176e3a1.1491838390.git.jslaby@suse.cz> X-Mailer: git-send-email 2.12.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1311 Lines: 41 From: Richard Genoud 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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 [rg] backport to 3.12 Signed-off-by: Richard Genoud Signed-off-by: Greg Kroah-Hartman Signed-off-by: Jiri Slaby --- drivers/tty/serial/atmel_serial.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index ab2e22bf54fd..04a809284d63 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1690,6 +1690,11 @@ static void atmel_flush_buffer(struct uart_port *port) UART_PUT_TCR(port, 0); atmel_port->pdc_tx.ofs = 0; } + /* + * in uart_flush_buffer(), the xmit circular buffer has just + * been cleared, so we have to reset its length accordingly. + */ + sg_dma_len(&atmel_port->sg_tx) = 0; } /* -- 2.12.2