From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EEFEB6FB4 for ; Mon, 19 Dec 2022 19:25:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5B9DBC433D2; Mon, 19 Dec 2022 19:25:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1671477955; bh=f/+yAd95iiio2Apg+GwBH2JRY4ZFWoFTDUTP3iRCvok=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AvVv1Kt19tnNAHSo/BolqH2TmafU78oRcFKUmqPZRu6U2s33AQSGCI8R+YKdfEwWy z79UEEkRR5nKmjudL6o0ytImCwuSpSpKoz0Ij966vYQ/CKOySgxWjrJZXrM4A05WxP d2cpYvskSIQOPNriWDrllWvQ4rhXE5qaPG6r2vzo= 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 6.0 18/28] USB: serial: f81534: fix division by zero on line-speed change Date: Mon, 19 Dec 2022 20:23:05 +0100 Message-Id: <20221219182944.977692157@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221219182944.179389009@linuxfoundation.org> References: <20221219182944.179389009@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Johan Hovold commit 188c9c2e0c7f4ae864113f80c40bafb394062271 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: 3aacac02f385 ("USB: serial: f81534: add high baud rate support") Cc: stable@vger.kernel.org # 4.16 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/f81534.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) --- a/drivers/usb/serial/f81534.c +++ b/drivers/usb/serial/f81534.c @@ -536,9 +536,6 @@ static int f81534_submit_writer(struct u static u32 f81534_calc_baud_divisor(u32 baudrate, u32 clockrate) { - if (!baudrate) - return 0; - /* Round to nearest divisor */ return DIV_ROUND_CLOSEST(clockrate, baudrate); } @@ -568,9 +565,14 @@ static int f81534_set_port_config(struct u32 baud_list[] = {baudrate, old_baudrate, F81534_DEFAULT_BAUD_RATE}; for (i = 0; i < ARRAY_SIZE(baud_list); ++i) { - idx = f81534_find_clk(baud_list[i]); + baudrate = baud_list[i]; + if (baudrate == 0) { + tty_encode_baud_rate(tty, 0, 0); + return 0; + } + + idx = f81534_find_clk(baudrate); if (idx >= 0) { - baudrate = baud_list[i]; tty_encode_baud_rate(tty, baudrate, baudrate); break; }