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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 8F2DDC76188 for ; Fri, 19 Jul 2019 04:13:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FDA42082F for ; Fri, 19 Jul 2019 04:13:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563509609; bh=Le25GrtF3G6bxZechcB+0t8lQQjNgYfnXpsHeSwnMoE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dfJCNMd2acDGBqCVKN8xmDDltY4Eio88yOect1ySTFTwY5PRCBe29rf7NheuPaoOp 7mhYhLg2KrJ/X/3Qsc529rN1wYi/GzFsP09c9WidtO7N2EZS1aFdUnrVmAQ5OGRpah 7upKWBkePfRBnXLFV5/yC8QiN29jbo5+dQHl1GbU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389230AbfGSEN1 (ORCPT ); Fri, 19 Jul 2019 00:13:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:49298 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389162AbfGSENW (ORCPT ); Fri, 19 Jul 2019 00:13:22 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 07AAB21873; Fri, 19 Jul 2019 04:13:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563509601; bh=Le25GrtF3G6bxZechcB+0t8lQQjNgYfnXpsHeSwnMoE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J74bg0uG8hnrr3uml8DadU9kJOdbm7CPbXHYa5IGQCLmLTn4OvMFxQmZv9SDKMtvH JfO/Y0u/8Q09Bd8fISmNGzIhUKh/jHs3kkwdW7P76aqGcZVHARfRqKVyyp3nIvRz5+ +XROi4OkoEVw/6sn99y8CWNeyv5CAZqFpXLgUeh8= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jorge Ramirez-Ortiz , Greg Kroah-Hartman , Sasha Levin , linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 11/45] tty: serial: msm_serial: avoid system lockup condition Date: Fri, 19 Jul 2019 00:12:30 -0400 Message-Id: <20190719041304.18849-11-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190719041304.18849-1-sashal@kernel.org> References: <20190719041304.18849-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jorge Ramirez-Ortiz [ Upstream commit ba3684f99f1b25d2a30b6956d02d339d7acb9799 ] The function msm_wait_for_xmitr can be taken with interrupts disabled. In order to avoid a potential system lockup - demonstrated under stress testing conditions on SoC QCS404/5 - make sure we wait for a bounded amount of time. Tested on SoC QCS404. Signed-off-by: Jorge Ramirez-Ortiz Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/msm_serial.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index 7dc8272c6b15..9027455c6be1 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -391,10 +391,14 @@ static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base) static inline void msm_wait_for_xmitr(struct uart_port *port) { + unsigned int timeout = 500000; + while (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY)) { if (msm_read(port, UART_ISR) & UART_ISR_TX_READY) break; udelay(1); + if (!timeout--) + break; } msm_write(port, UART_CR_CMD_RESET_TX_READY, UART_CR); } -- 2.20.1