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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 84020C38A2A for ; Thu, 7 May 2020 17:21:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 63BDD21835 for ; Thu, 7 May 2020 17:21:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726356AbgEGRVk (ORCPT ); Thu, 7 May 2020 13:21:40 -0400 Received: from mga17.intel.com ([192.55.52.151]:18693 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726222AbgEGRVk (ORCPT ); Thu, 7 May 2020 13:21:40 -0400 IronPort-SDR: cM+Yedsq6jkDtKE2D9Ke1MlcyZHSD1bwfkm7JyAEpLhfFlLChWaMvmtH9yH3tzrD5BQUchRkKU 509LU12gci4Q== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 May 2020 10:21:40 -0700 IronPort-SDR: GK+1icHNFj19CJ+91hjNV73ayYdaExpKxnPX4/gEJDQJzbISNiD+HHK6RgHmxhcKuVCFKVYumN tS6M1fgmCP/A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,364,1583222400"; d="scan'208";a="285066680" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.157]) ([10.237.72.157]) by fmsmga004.fm.intel.com with ESMTP; 07 May 2020 10:21:34 -0700 Subject: Re: [PATCH V2] mmc: core: Fix recursive locking issue in CQE recovery path To: Veerabhadrarao Badiganti , ulf.hansson@linaro.org Cc: stummala@codeaurora.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, Sarthak Garg , stable@vger.kernel.org, Yoshihiro Shimoda , Baolin Wang , Kate Stewart , Allison Randal , Thomas Gleixner , Linus Walleij References: <1588775643-18037-3-git-send-email-vbadigan@codeaurora.org> <1588868135-31783-1-git-send-email-vbadigan@codeaurora.org> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: Date: Thu, 7 May 2020 20:21:55 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <1588868135-31783-1-git-send-email-vbadigan@codeaurora.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 7/05/20 7:15 pm, Veerabhadrarao Badiganti wrote: > From: Sarthak Garg > > Consider the following stack trace > > -001|raw_spin_lock_irqsave > -002|mmc_blk_cqe_complete_rq > -003|__blk_mq_complete_request(inline) > -003|blk_mq_complete_request(rq) > -004|mmc_cqe_timed_out(inline) > -004|mmc_mq_timed_out > > mmc_mq_timed_out acquires the queue_lock for the first > time. The mmc_blk_cqe_complete_rq function also tries to acquire > the same queue lock resulting in recursive locking where the task > is spinning for the same lock which it has already acquired leading > to watchdog bark. > > Fix this issue with the lock only for the required critical section. > > Cc: > Fixes: 1e8e55b67030 ("mmc: block: Add CQE support") > Suggested-by: Sahitya Tummala > Signed-off-by: Sarthak Garg Acked-by: Adrian Hunter > --- > drivers/mmc/core/queue.c | 13 ++++--------- > 1 file changed, 4 insertions(+), 9 deletions(-) > > diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c > index 25bee3d..b5fd3bc 100644 > --- a/drivers/mmc/core/queue.c > +++ b/drivers/mmc/core/queue.c > @@ -107,7 +107,7 @@ static enum blk_eh_timer_return mmc_cqe_timed_out(struct request *req) > case MMC_ISSUE_DCMD: > if (host->cqe_ops->cqe_timeout(host, mrq, &recovery_needed)) { > if (recovery_needed) > - __mmc_cqe_recovery_notifier(mq); > + mmc_cqe_recovery_notifier(mrq); > return BLK_EH_RESET_TIMER; > } > /* No timeout (XXX: huh? comment doesn't make much sense) */ > @@ -127,18 +127,13 @@ static enum blk_eh_timer_return mmc_mq_timed_out(struct request *req, > struct mmc_card *card = mq->card; > struct mmc_host *host = card->host; > unsigned long flags; > - int ret; > + bool ignore_tout; > > spin_lock_irqsave(&mq->lock, flags); > - > - if (mq->recovery_needed || !mq->use_cqe || host->hsq_enabled) > - ret = BLK_EH_RESET_TIMER; > - else > - ret = mmc_cqe_timed_out(req); > - > + ignore_tout = mq->recovery_needed || !mq->use_cqe || host->hsq_enabled; > spin_unlock_irqrestore(&mq->lock, flags); > > - return ret; > + return ignore_tout ? BLK_EH_RESET_TIMER : mmc_cqe_timed_out(req); > } > > static void mmc_mq_recovery_handler(struct work_struct *work) >