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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 3471BC433FF for ; Mon, 29 Jul 2019 19:40:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDF3921773 for ; Mon, 29 Jul 2019 19:40:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429210; bh=pLP+vHYWLnhimDZ0n0v57hSXCodcbj60OSQFN8CvEMI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ncxc+bxCRKrzOf6RtjqeZ9eoAv1rvScdHpiy8U2MqeA/z/WxiDfOgZaBHsEYLGczB wDjx2r1n0dGDsOgU1mA+pXVoHQWdpW1/CmSMT17RSnihIPS766aKFH1/b2ugQr6E0Z 9TR06Onf5D0tCoiY6df3z8SGjFshnxTq04WKK5rs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388639AbfG2TkI (ORCPT ); Mon, 29 Jul 2019 15:40:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:55356 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389088AbfG2TkF (ORCPT ); Mon, 29 Jul 2019 15:40:05 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ED8072054F; Mon, 29 Jul 2019 19:40:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429205; bh=pLP+vHYWLnhimDZ0n0v57hSXCodcbj60OSQFN8CvEMI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bxGBi4xulilZ1OzrcAzSD8wwTo05X4hwl5Z3VXOa1RWWQ9v4i1cCzyeo4k3SwFZt2 hPaB5Uygfj0qLP13wAAW6tWVQJLiO4St/Y0vM2P9RZ1wIIT1aTO6qS+p9uXRuwBqJ6 pN6eSqZwMwqesRHiC1ey4jR1bVKoRTIYvXau8z14= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jorge Ramirez-Ortiz , Sasha Levin Subject: [PATCH 4.19 024/113] tty: serial: msm_serial: avoid system lockup condition Date: Mon, 29 Jul 2019 21:21:51 +0200 Message-Id: <20190729190701.631193260@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190655.455345569@linuxfoundation.org> References: <20190729190655.455345569@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ 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