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 X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 394EBC11F6C for ; Sat, 10 Jul 2021 02:38:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F4B7613CA for ; Sat, 10 Jul 2021 02:38:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234691AbhGJClQ (ORCPT ); Fri, 9 Jul 2021 22:41:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:58368 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235599AbhGJCji (ORCPT ); Fri, 9 Jul 2021 22:39:38 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 59730613F5; Sat, 10 Jul 2021 02:35:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625884517; bh=RziDAp4BQsITzVInvhjMeZNe1otkpJ26f5BdXuv1mXc=; h=From:To:Cc:Subject:Date:From; b=CVxyO3JofkZrCZ3+yyDKX1z2itvaBp4K8nw8YpCP8kv3wTMNDhUn+TB3nXrsPyDxm F5syaJLMp8sUhHg8Fswtn/YXw08ZOW9BwhR7bFviwKoLlDyZ7d4v2+kVoGNH9CxuCi 4ZrC+i3al/UMyjKt2+sN3mq0izJqv+HmeMy7ues24CrLIQ3AC6CUDyZX84Nblvo2hH kcdeRlXBGtzm9IzcOO5E3r/WrZ/wamaxSRjK5r5kALE/m56nADIsDCgmJUbIL5KbxI JZV0SjyHjdppsrnzubchv6bakEZ8gBwstPYGvoeF/+q7J4Y4LF33N04A4G+GitGNLf pM1Szk13eIb7Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sherry Sun , Greg Kroah-Hartman , Sasha Levin , linux-serial@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 01/33] tty: serial: fsl_lpuart: fix the potential risk of division or modulo by zero Date: Fri, 9 Jul 2021 22:34:43 -0400 Message-Id: <20210710023516.3172075-1-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sherry Sun [ Upstream commit fcb10ee27fb91b25b68d7745db9817ecea9f1038 ] We should be very careful about the register values that will be used for division or modulo operations, althrough the possibility that the UARTBAUD register value is zero is very low, but we had better to deal with the "bad data" of hardware in advance to avoid division or modulo by zero leading to undefined kernel behavior. Signed-off-by: Sherry Sun Link: https://lore.kernel.org/r/20210427021226.27468-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/fsl_lpuart.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index cebebdcd091c..3d5fe53988e5 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -1998,6 +1998,9 @@ lpuart32_console_get_options(struct lpuart_port *sport, int *baud, bd = lpuart32_read(&sport->port, UARTBAUD); bd &= UARTBAUD_SBR_MASK; + if (!bd) + return; + sbr = bd; uartclk = clk_get_rate(sport->clk); /* -- 2.30.2