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=ham 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 5087DC76195 for ; Fri, 19 Jul 2019 04:26:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 20B2420873 for ; Fri, 19 Jul 2019 04:26:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563510385; bh=9HLLdbZ8ShZ3G6w+fG9xmdaFeWkpP1oPw+qdqufeN4k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=bU3jflujfibkyTC3+jJvm9h+Cjr0RmKpQBxci4BTa8GJSjqKJczfXGoJhnr4yv90K mTCHteWrn2HX4k9ExT9Pw/+mnf4siw//w63WkOOHAP+uYbCIwggQM+wwmdvuq3ltWg OMR/zcG92JNj8KJ9JK9UwbsNoWYlccNKcvzMSydI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388622AbfGSE0Y (ORCPT ); Fri, 19 Jul 2019 00:26:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:42666 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733046AbfGSEIW (ORCPT ); Fri, 19 Jul 2019 00:08:22 -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 C5D76218A0; Fri, 19 Jul 2019 04:08:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563509301; bh=9HLLdbZ8ShZ3G6w+fG9xmdaFeWkpP1oPw+qdqufeN4k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y6rorNUz72GSl3iEAdUkaefK2xSO8g5luNujcGcDsucpeQSRbdF5ZzdCtiZurWspX X+hWwBZuNTV5nmkJVx2qpHS53TGeNdpnLp66a5ln0tQV/ffP9ShVRXXsCGCZC3Hude W8UOYubjv69Og+ImwJmhcIrBZyrp72Vu0ncUZVDU= 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 4.19 024/101] tty: serial: msm_serial: avoid system lockup condition Date: Fri, 19 Jul 2019 00:06:15 -0400 Message-Id: <20190719040732.17285-24-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190719040732.17285-1-sashal@kernel.org> References: <20190719040732.17285-1-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 0f41b936da03..310bbae515b0 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -383,10 +383,14 @@ 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