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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 BF364C2BA19 for ; Tue, 21 Apr 2020 06:03:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C8DB20857 for ; Tue, 21 Apr 2020 06:03:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="GXTClrM0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725989AbgDUGDl (ORCPT ); Tue, 21 Apr 2020 02:03:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725901AbgDUGDk (ORCPT ); Tue, 21 Apr 2020 02:03:40 -0400 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C707C061A0F for ; Mon, 20 Apr 2020 23:03:39 -0700 (PDT) Received: by mail-pj1-x1043.google.com with SMTP id a7so923911pju.2 for ; Mon, 20 Apr 2020 23:03:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Q6cPJRXuN2aseU4O71Njq6zpEr8MeM+xwy6CdRmNFGs=; b=GXTClrM0Xef14YYO+Wsv0lPyfAZ+8oWUatmmgc94tRA6gmj3b2cSEO+Ec8CtxzuylU rNWE1AqAcWIXvzJHVP/XugZlkE0QUpRweu0VOWE8QhNMQ+UcrUmp4K97IGrgHV0OINQV 7t+BY637qa47LbuklYwrEYxxvHgjSgyj+/qn386Lsg4MT7B0nfXJ/49+LXzPxE+s88GU pAYaPch+02X8DBPJqw8o44H4mt9+tBgUQ8Yrli8nf1dqGwkjBMJGA7AUoGPZaB5TXmpM /Q3GPwJkoWFq+yJaS8RcvR6mHDzXyqirM1dsW6g8r1aNpKO4bHUxjnkgnL2RJiF/2vK4 n9pQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=Q6cPJRXuN2aseU4O71Njq6zpEr8MeM+xwy6CdRmNFGs=; b=siwG6JwhYeVtoadecCHXyFLCLiYqjoE/HmVFFknUVvM3FLTjbrjpQQFe1W+1yUjA+Z tyUMm3Zb7qYtdtxL4JZm7SsXAEAJMvwvJN7ZiMmKtvxKRt64QxtmuGxneJ+1npmsSHA4 lrlYk5CGWLutmPUmYYmtYa4AGdV+srcosxwkuR5vJWrdyY2uclERndbr6PPcnqz35N60 8epYl/CojvZzProZtojc8U/ZzrADyiwlHVGX1ukPuSkH3/zF37FYS8cDnosmzWmRZlIh mo9RCajPnxVR3xgwWw63wj1m5eOM/VU1qoKEv1pUeXBXuJytyd1MjoMMsAztyvRs7Y+g wqKg== X-Gm-Message-State: AGi0PuaI2FvqIcTVGn8ZrsUMrUyiH/g9fmJd0ngZd/dxKKaEmC+Sxid3 rlIe/jtCede5SNU0YIo0gCou X-Google-Smtp-Source: APiQypILZKe0CW0DyxcFIDHPPUV8NGLoLz5o2QKVAvqdp2IAl1MD+vpps3yPj3zb0YkFpncR2nhcTA== X-Received: by 2002:a17:902:ac87:: with SMTP id h7mr7740737plr.119.1587449018703; Mon, 20 Apr 2020 23:03:38 -0700 (PDT) Received: from Mani-XPS-13-9360 ([2409:4072:6289:7463:c15b:2de1:b77e:d971]) by smtp.gmail.com with ESMTPSA id c144sm1342511pfb.172.2020.04.20.23.03.36 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Mon, 20 Apr 2020 23:03:38 -0700 (PDT) Date: Tue, 21 Apr 2020 11:33:33 +0530 From: Manivannan Sadhasivam To: Dan Carpenter Cc: linux-arm-msm@vger.kernel.org, kernel-janitors@vger.kernel.org, hemantk@codeaurora.org Subject: Re: [bug report] bus: mhi: core: Add support for data transfer Message-ID: <20200421060333.GB4327@Mani-XPS-13-9360> References: <20200407135559.GA109574@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200407135559.GA109574@mwanda> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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); > ^^^^^^^^^^^^^^^ > The caller is already holding this lock. > This function will be called from multiple places. It needs to have the chan->lock on its own. I thought about dropping the lock in parse_xfer_event() before calling this function but that won't really solve any issue since read_locks are recursive and by doing so we are only making the static checkers happy. So I'd consider this bug report as false positive. Thanks, 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