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=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 B8389C433FF for ; Mon, 29 Jul 2019 19:47:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7DF772054F for ; Mon, 29 Jul 2019 19:47:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429660; bh=MqF8HHLqzYEMhjxa/Iw6PcCVntom90MdjouzgeIFzrk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aCt/hIKWThDAO432sjT6Lred/Bg9BNLOY3Dt3yeIQnhXZH/vpYH1Zsj2aNZ/GQsi8 0rLvLJPLfuZ8F7U4Z45vUb4brjoSQ5WftTbGxODSXQevo1Jrd8LtWRhnbq7c5DWcp5 I6vY34FtgzF9RCP2yuFkDyXZMirLpCr9LwYafB+8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390365AbfG2Tri (ORCPT ); Mon, 29 Jul 2019 15:47:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:37270 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390357AbfG2Trc (ORCPT ); Mon, 29 Jul 2019 15:47:32 -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 6E92420C01; Mon, 29 Jul 2019 19:47:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429651; bh=MqF8HHLqzYEMhjxa/Iw6PcCVntom90MdjouzgeIFzrk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Rfcm+isbpG+Uzz/gE6CXrSNrO8B3pIEy/PneiZJUeBj/9aVoJOh8/yO3osJc1023H Jfl0dLafByIoLbvBn4JDcr+a7iwCWdqcGVcxI/ByshiqTaLAOjJIJHPVknkWummbfB xFUxUj1pqSri+gb6DCQmP2O6Q18fYWsy4M/zOcyA= 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 5.2 051/215] tty: serial: msm_serial: avoid system lockup condition Date: Mon, 29 Jul 2019 21:20:47 +0200 Message-Id: <20190729190749.370988457@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190739.971253303@linuxfoundation.org> References: <20190729190739.971253303@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 23833ad952ba..3657a24913fc 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