From patchwork Fri Dec 18 07:16:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chaotian Jing X-Patchwork-Id: 11981309 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 3E361C4361B for ; Fri, 18 Dec 2020 07:17:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1388023A23 for ; Fri, 18 Dec 2020 07:17:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731527AbgLRHRB (ORCPT ); Fri, 18 Dec 2020 02:17:01 -0500 Received: from mailgw02.mediatek.com ([210.61.82.184]:54995 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1732322AbgLRHRA (ORCPT ); Fri, 18 Dec 2020 02:17:00 -0500 X-UUID: e68527d1d73447cab287e8ae6f90a952-20201218 X-UUID: e68527d1d73447cab287e8ae6f90a952-20201218 Received: from mtkcas11.mediatek.inc [(172.21.101.40)] by mailgw02.mediatek.com (envelope-from ) (Cellopoint E-mail Firewall v4.1.14 Build 0819 with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1315769706; Fri, 18 Dec 2020 15:16:15 +0800 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs07n1.mediatek.inc (172.21.101.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 18 Dec 2020 15:16:13 +0800 Received: from localhost.localdomain (10.17.3.153) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 18 Dec 2020 15:16:12 +0800 From: Chaotian Jing To: Ulf Hansson CC: Chaotian Jing , Matthias Brugger , , , , , Subject: [PATCH] mmc: mediatek: fix race condition between msdc_request_timeout and irq Date: Fri, 18 Dec 2020 15:16:11 +0800 Message-ID: <20201218071611.12276-1-chaotian.jing@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org when get request SW timeout, if CMD/DAT xfer done irq coming right now, then there is race between the msdc_request_timeout work and irq handler, and the host->cmd and host->data may set to NULL in irq handler. also, current flow ensure that only one path can go to msdc_request_done(), so no need check the return value of cancel_delayed_work(). Signed-off-by: Chaotian Jing --- drivers/mmc/host/mtk-sd.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c index de09c6347524..898ed1b023df 100644 --- a/drivers/mmc/host/mtk-sd.c +++ b/drivers/mmc/host/mtk-sd.c @@ -1127,13 +1127,13 @@ static void msdc_track_cmd_data(struct msdc_host *host, static void msdc_request_done(struct msdc_host *host, struct mmc_request *mrq) { unsigned long flags; - bool ret; - ret = cancel_delayed_work(&host->req_timeout); - if (!ret) { - /* delay work already running */ - return; - } + /* + * No need check the return value of cancel_delayed_work, as only ONE + * path will go here! + */ + cancel_delayed_work(&host->req_timeout); + spin_lock_irqsave(&host->lock, flags); host->mrq = NULL; spin_unlock_irqrestore(&host->lock, flags); @@ -1155,7 +1155,7 @@ static bool msdc_cmd_done(struct msdc_host *host, int events, bool done = false; bool sbc_error; unsigned long flags; - u32 *rsp = cmd->resp; + u32 *rsp; if (mrq->sbc && cmd == mrq->cmd && (events & (MSDC_INT_ACMDRDY | MSDC_INT_ACMDCRCERR @@ -1176,6 +1176,7 @@ static bool msdc_cmd_done(struct msdc_host *host, int events, if (done) return true; + rsp = cmd->resp; sdr_clr_bits(host->base + MSDC_INTEN, cmd_ints_mask); @@ -1363,7 +1364,7 @@ static void msdc_data_xfer_next(struct msdc_host *host, static bool msdc_data_xfer_done(struct msdc_host *host, u32 events, struct mmc_request *mrq, struct mmc_data *data) { - struct mmc_command *stop = data->stop; + struct mmc_command *stop; unsigned long flags; bool done; unsigned int check_data = events & @@ -1379,6 +1380,7 @@ static bool msdc_data_xfer_done(struct msdc_host *host, u32 events, if (done) return true; + stop = data->stop; if (check_data || (stop && stop->error)) { dev_dbg(host->dev, "DMA status: 0x%8X\n",