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 D3BAA6FB4 for ; Mon, 19 Dec 2022 19:24:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 469E7C433D2; Mon, 19 Dec 2022 19:24:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1671477869; bh=oMAzkoQPevLcgi40z9VdWz78/mwiPrfO1A/FqoCJaeI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eHeXUWia1Nv/dTqFc0o1uGtoj9Uyoy1xComkOxyejq9VPjwAQ9nTafTLjrE/V/Q24 fU6+gTZt8HXGlCZUf2MnC2uV8fDx2ZJ3DZhnIaCrJ4IfOFOdJHb3EVRtBcmdEsKEJZ 5rpj+EbuV7DNQ/chx8G1aUH9qTyMdIxCivT8tf0Q= 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 6.1 15/25] USB: serial: f81232: fix division by zero on line-speed change Date: Mon, 19 Dec 2022 20:22:54 +0100 Message-Id: <20221219182944.041582664@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221219182943.395169070@linuxfoundation.org> References: <20221219182943.395169070@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 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 @@ -130,9 +130,6 @@ 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); } @@ -498,9 +495,14 @@ 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; }