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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 A2ECBC2BB1D for ; Fri, 17 Apr 2020 03:37:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F7C8221E8 for ; Fri, 17 Apr 2020 03:37:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="mIxePzaY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726521AbgDQDhW (ORCPT ); Thu, 16 Apr 2020 23:37:22 -0400 Received: from mail26.static.mailgun.info ([104.130.122.26]:30907 "EHLO mail26.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725768AbgDQDhU (ORCPT ); Thu, 16 Apr 2020 23:37:20 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1587094640; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=Yzp8Njt8hvEzJ7nuvdW0uOb2SLTDSNRmMzbAf5iD5kA=; b=mIxePzaYvkpv0FNxPTetLzNNL09wBGz2umU5/cbNIWodUWOQ4PT2DHqq31g7naqMkNctzTen ABlLyMi6RPQuA86liG6xjW0YuDHoVrlAuxH0bpuigkjb/OhQVbUevbOWyTDL56fHZxa6HepB TfjyE3rBhyoaZ4Bc0y6rxQnoKpA= X-Mailgun-Sending-Ip: 104.130.122.26 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5e99246d.7f6a9612e810-smtp-out-n04; Fri, 17 Apr 2020 03:37:17 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id C6A5EC433BA; Fri, 17 Apr 2020 03:37:17 +0000 (UTC) Received: from [10.46.162.249] (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: hemantk) by smtp.codeaurora.org (Postfix) with ESMTPSA id 1E45DC433F2; Fri, 17 Apr 2020 03:37:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 1E45DC433F2 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=hemantk@codeaurora.org Subject: Re: [bug report] bus: mhi: core: Add support for data transfer To: Manivannan Sadhasivam , Dan Carpenter Cc: linux-arm-msm@vger.kernel.org, kernel-janitors@vger.kernel.org References: <20200407135559.GA109574@mwanda> <20200407143304.GH2442@Mani-XPS-13-9360> From: Hemant Kumar Message-ID: Date: Thu, 16 Apr 2020 20:37:16 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20200407143304.GH2442@Mani-XPS-13-9360> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 4/7/20 7:33 AM, Manivannan Sadhasivam wrote: > Hi Dan, > > On Tue, Apr 07, 2020 at 04:55:59PM +0300, Dan Carpenter wrote: >> Hello Manivannan Sadhasivam, >> >> The patch 189ff97cca53: "bus: mhi: core: Add support for data >> transfer" from Feb 20, 2020, leads to the following static checker >> warning: >> >> drivers/bus/mhi/core/main.c:1153 mhi_queue_buf() >> error: double locked 'mhi_chan->lock' (orig line 1110) >> >> drivers/bus/mhi/core/main.c >> 1142 } >> 1143 >> 1144 /* Toggle wake to exit out of M2 */ >> 1145 mhi_cntrl->wake_toggle(mhi_cntrl); >> 1146 >> 1147 if (mhi_chan->dir == DMA_TO_DEVICE) >> 1148 atomic_inc(&mhi_cntrl->pending_pkts); >> 1149 >> 1150 if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl))) { >> 1151 unsigned long flags; >> 1152 >> 1153 read_lock_irqsave(&mhi_chan->lock, flags); parse_xfer_event is taking read lock : read_lock_bh(&mhi_chan->lock); first and later mhi_queue_buf takes read lock: read_lock_irqsave(&mhi_chan->lock, flags); Both are read locks which are recursive, is this problematic ? >> ^^^^^^^^^^^^^^^ >> The caller is already holding this lock. >> > Hmm. We have one internal user of this function and that's where the locking > has gone wrong. Will fix it. > > Thanks for reporting! > > Regards, > Mani > >> 1154 mhi_ring_chan_db(mhi_cntrl, mhi_chan); >> 1155 read_unlock_irqrestore(&mhi_chan->lock, flags); >> 1156 } >> 1157 >> 1158 read_unlock_irqrestore(&mhi_cntrl->pm_lock, flags); >> 1159 >> 1160 return 0; >> 1161 } >> 1162 EXPORT_SYMBOL_GPL(mhi_queue_buf); >> >> regards, >> dan carpenter -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project