From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF731C54EBE for ; Mon, 16 Jan 2023 16:18:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232619AbjAPQSD (ORCPT ); Mon, 16 Jan 2023 11:18:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32984 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232664AbjAPQRK (ORCPT ); Mon, 16 Jan 2023 11:17:10 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE8FF27D6F for ; Mon, 16 Jan 2023 08:09:50 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 6A959B81081 for ; Mon, 16 Jan 2023 16:09:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5872C433D2; Mon, 16 Jan 2023 16:09:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673885388; bh=mjktX0nTWiTqRVdhL7ebr7CLl4N979cSR4fCb1tSuI4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hsj+9LGcKBQfnP4zgY6EbRtz71bDrbjykd7nggqVB907js9jANgluAbAcZAuRkqwk +HFdbYkd1BSnNKIF+AVVFwCwAx0LPdE9chYWjTh3pchdgJbcHx4DBUY3tgvN4frLA9 u68vO/N/S/9Ol20FKymzwhZNpw4HitTNFMJvLSQo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Ji-Ze Hong (Peter Hong)" , Johan Hovold Subject: [PATCH 5.4 009/658] USB: serial: f81232: fix division by zero on line-speed change Date: Mon, 16 Jan 2023 16:41:37 +0100 Message-Id: <20230116154910.077379010@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154909.645460653@linuxfoundation.org> References: <20230116154909.645460653@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Johan Hovold commit a08ca6ebafe615c9028c53fc4c9e6c9b2b1f2888 upstream. The driver leaves the line speed unchanged in case a requested speed is not supported. Make sure to handle the case where the current speed is B0 (hangup) without dividing by zero when determining the clock source. Fixes: 268ddb5e9b62 ("USB: serial: f81232: add high baud rate support") Cc: stable@vger.kernel.org # 5.2 Cc: Ji-Ze Hong (Peter Hong) Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/f81232.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) --- a/drivers/usb/serial/f81232.c +++ b/drivers/usb/serial/f81232.c @@ -78,9 +78,6 @@ static u8 const clock_table[] = { F81232 static int calc_baud_divisor(speed_t baudrate, speed_t clockrate) { - if (!baudrate) - return 0; - return DIV_ROUND_CLOSEST(clockrate, baudrate); } @@ -423,9 +420,14 @@ static void f81232_set_baudrate(struct t speed_t baud_list[] = { baudrate, old_baudrate, F81232_DEF_BAUDRATE }; for (i = 0; i < ARRAY_SIZE(baud_list); ++i) { - idx = f81232_find_clk(baud_list[i]); + baudrate = baud_list[i]; + if (baudrate == 0) { + tty_encode_baud_rate(tty, 0, 0); + return; + } + + idx = f81232_find_clk(baudrate); if (idx >= 0) { - baudrate = baud_list[i]; tty_encode_baud_rate(tty, baudrate, baudrate); break; }