From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932372AbcFIVRw (ORCPT ); Thu, 9 Jun 2016 17:17:52 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:50715 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932322AbcFIVRr (ORCPT ); Thu, 9 Jun 2016 17:17:47 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: =?UTF-8?q?David=20M=C3=BCller?= , Greg Kroah-Hartman , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 034/206] serial: 8250_pci: fix divide error bug if baud rate is 0 Date: Thu, 9 Jun 2016 14:14:03 -0700 Message-Id: <1465507015-23052-35-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1465507015-23052-1-git-send-email-kamal@canonical.com> References: <1465507015-23052-1-git-send-email-kamal@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Extended-Stable: 4.2 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt12 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: =?UTF-8?q?David=20M=C3=BCller?= commit 6f210c18c1c0f016772c8cd51ae12a02bfb9e7ef upstream. Since commit 21947ba654a6 ("serial: 8250_pci: replace switch-case by formula"), the 8250 driver crashes in the byt_set_termios() function with a divide error. This is caused by the fact that a baud rate of 0 (B0) is not handled properly. Fix it by falling back to B9600 in this case. Signed-off-by: David Müller Fixes: 21947ba654a6 ("serial: 8250_pci: replace switch-case by formula") Suggested-by: Andy Shevchenko Reviewed-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa --- drivers/tty/serial/8250/8250_pci.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index 78aeb11..9850bbf 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -1402,6 +1402,9 @@ byt_set_termios(struct uart_port *p, struct ktermios *termios, unsigned long m, n; u32 reg; + /* Gracefully handle the B0 case: fall back to B9600 */ + fuart = fuart ? fuart : 9600 * 16; + /* Get Fuart closer to Fref */ fuart *= rounddown_pow_of_two(fref / fuart); -- 2.7.4