From patchwork Thu Aug 20 09:22:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 265547 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83F3DC433E4 for ; Thu, 20 Aug 2020 11:40:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5FF69204EA for ; Thu, 20 Aug 2020 11:40:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597923637; bh=n/0+0UGv4O9BLXYPaeUxV3WyDmPOcZAe99nVn9byrSg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=g7EAORh+qBNOYb+b2SAFuk35ouGXtNhKUe6mfKjvCUP/MkdCKDF45kLjZETrppXO0 vABNScD1QqoL8eFo3fmMnKcVfOs6sX+geuzOU5UopSxbdjs+G330FuqQ9GMiGzvjlI Cjj7siEALC/x8vu27tH3F4+Gq5RHGInOTbJuyH6Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729157AbgHTLkg (ORCPT ); Thu, 20 Aug 2020 07:40:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:60042 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730637AbgHTKE7 (ORCPT ); Thu, 20 Aug 2020 06:04:59 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 54CB02173E; Thu, 20 Aug 2020 10:04:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597917898; bh=n/0+0UGv4O9BLXYPaeUxV3WyDmPOcZAe99nVn9byrSg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2aGC7uCH8g7Ci3UA2LbeUUBVmS1saPr0PfgJ0OZyBOGEBYqZ4PRyF7G0COSQ3wmWk PQl0oCjTydL8MjvTHPHY2qGpAg5yQ2yv0VpywtRm1AgR9+U2A2ZCYqaVQDSf0CykgY PG4cMex2hC3vPx6dO2r9kcTgQCcGU/2+4tbO/2so= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johan Hovold , Sasha Levin Subject: [PATCH 4.9 195/212] USB: serial: ftdi_sio: fix break and sysrq handling Date: Thu, 20 Aug 2020 11:22:48 +0200 Message-Id: <20200820091612.210419265@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200820091602.251285210@linuxfoundation.org> References: <20200820091602.251285210@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Johan Hovold [ Upstream commit 733fff67941dad64b8a630450b8372b1873edc41 ] Only the last NUL in a packet should be flagged as a break character, for example, to avoid dropping unrelated characters when IGNBRK is set. Also make sysrq work by consuming the break character instead of having it immediately cancel the sysrq request, and by not processing it prematurely to avoid triggering a sysrq based on an unrelated character received in the same packet (which was received *before* the break). Note that the break flag can be left set also for a packet received immediately following a break and that and an ending NUL in such a packet will continue to be reported as a break as there's no good way to tell it apart from an actual break. Tested on FT232R and FT232H. Fixes: 72fda3ca6fc1 ("USB: serial: ftd_sio: implement sysrq handling on break") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold Signed-off-by: Sasha Levin --- drivers/usb/serial/ftdi_sio.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 0c8b24ff44a05..bb29d5fd032fd 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -2054,6 +2054,7 @@ static int ftdi_process_packet(struct usb_serial_port *port, struct ftdi_private *priv, unsigned char *buf, int len) { unsigned char status; + bool brkint = false; int i; char flag; @@ -2105,13 +2106,17 @@ static int ftdi_process_packet(struct usb_serial_port *port, */ flag = TTY_NORMAL; if (buf[1] & FTDI_RS_ERR_MASK) { - /* Break takes precedence over parity, which takes precedence - * over framing errors */ - if (buf[1] & FTDI_RS_BI) { - flag = TTY_BREAK; + /* + * Break takes precedence over parity, which takes precedence + * over framing errors. Note that break is only associated + * with the last character in the buffer and only when it's a + * NUL. + */ + if (buf[1] & FTDI_RS_BI && buf[len - 1] == '\0') { port->icount.brk++; - usb_serial_handle_break(port); - } else if (buf[1] & FTDI_RS_PE) { + brkint = true; + } + if (buf[1] & FTDI_RS_PE) { flag = TTY_PARITY; port->icount.parity++; } else if (buf[1] & FTDI_RS_FE) { @@ -2127,8 +2132,13 @@ static int ftdi_process_packet(struct usb_serial_port *port, port->icount.rx += len - 2; - if (port->port.console && port->sysrq) { + if (brkint || (port->port.console && port->sysrq)) { for (i = 2; i < len; i++) { + if (brkint && i == len - 1) { + if (usb_serial_handle_break(port)) + return len - 3; + flag = TTY_BREAK; + } if (usb_serial_handle_sysrq_char(port, buf[i])) continue; tty_insert_flip_char(&port->port, buf[i], flag);