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=-17.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 85DF6C433E9 for ; Wed, 24 Feb 2021 09:56:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3AACF64EC8 for ; Wed, 24 Feb 2021 09:56:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234431AbhBXJ4I (ORCPT ); Wed, 24 Feb 2021 04:56:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234709AbhBXJzy (ORCPT ); Wed, 24 Feb 2021 04:55:54 -0500 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB669C061786 for ; Wed, 24 Feb 2021 01:55:08 -0800 (PST) Received: by mail-pj1-x102a.google.com with SMTP id o6so972252pjf.5 for ; Wed, 24 Feb 2021 01:55:08 -0800 (PST) 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=r/zwiQ7rKCXTlfSUTQ7/OYwTvidrNvId9rOU1ZPgLoI=; b=XgHs8ypljKL7JMf1XzYByopmcfyRVZI+/UersmvMswPSqXnZ3e/32gdY02owtBDIo+ zfIV+rbWjH93TkS6P/M9u9lLdJSQf/qkHzb7ozu06o6AUJF9KIZHWISE1MYtjHZGBlC8 daLPjg3p1Mq9fxCx/JIMw60QFtN3fHp6bFHea9+Z0+cAdKsmdYd9B6K2jJKYzYlTwuSC Jc9L8iV218HPt3p4kCJHaAQHQqSBXZGsVGblqUdkl1GYdSDC8W9nhSeYQ+1h1oYbLrju JiHlcFc3zdf5J1cMcdj+3tupyG5rGqm2HZfSigFH/oSmdF9RXZcuS09XZRXIklVnbVq7 /dAQ== 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=r/zwiQ7rKCXTlfSUTQ7/OYwTvidrNvId9rOU1ZPgLoI=; b=Qx3LD9oP9odU/WtQLHSOsKfJe9JGtCNq1wL89DabV8ZP9HX8/PCUgaxJCi2X7Su5zK 9VEeFBvrD8K0+N2BzzuGGSX9h7TvRRqSbwdW6bPl4VH5swzLsUScfSlGOLhEHj2s8Yu0 lyG9j/yt54t9ueCegJMA1OwlPT9fc+Q+w/dbq9KJNGorY8InOoPMC81twOBySArUVndC z9QW/fxA85x5/LQhlIrrwRf19nHbyT3LISFvJLVd+UFLMppdDaa64crz5rT4OeebdeFf wPshfiee+/yG9uHXoplVqE620wG0VArUnf3Fcv4M/QpKSw8A1yjQ5NfbDuFFgglnNt7e Jlvw== X-Gm-Message-State: AOAM531PKgJxtgGmN9oETTsj/39hzZ67a41kriV3x25jxGHQ6Ji65rq5 D8OHA8nw0uzAq7iPw91pMuZrVybOQjPo X-Google-Smtp-Source: ABdhPJxDoLf2AFc1SZlfvTrkELEXdYS9phIZp/94yG32uYo0HOuTqyRCATolHEGImEE1SIbO7KyMdA== X-Received: by 2002:a17:902:b609:b029:e3:4b8d:994 with SMTP id b9-20020a170902b609b02900e34b8d0994mr31524024pls.44.1614160508295; Wed, 24 Feb 2021 01:55:08 -0800 (PST) Received: from work ([103.66.79.25]) by smtp.gmail.com with ESMTPSA id b22sm2148547pfo.23.2021.02.24.01.55.06 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Wed, 24 Feb 2021 01:55:07 -0800 (PST) Date: Wed, 24 Feb 2021 15:25:04 +0530 From: Manivannan Sadhasivam To: Jeffrey Hugo Cc: hemantk@codeaurora.org, bbhatt@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] bus: mhi: core: Check state before processing power_down Message-ID: <20210224095504.GQ27945@work> References: <1613580211-22744-1-git-send-email-jhugo@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1613580211-22744-1-git-send-email-jhugo@codeaurora.org> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 17, 2021 at 09:43:31AM -0700, Jeffrey Hugo wrote: > We cannot process a power_down if the power state is DISABLED. There is > no valid mhi_ctxt in that case, so attepting to process the power_down > will likely result in a null pointer dereference. If the power state is > DISABLED, there is nothing to do anyways, so just bail early. > > Signed-off-by: Jeffrey Hugo > --- > > v2: Fix subject and tweak the locking to avoid needless lock/unlock/relock > > drivers/bus/mhi/core/pm.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c > index 56ba3ab..47f6621 100644 > --- a/drivers/bus/mhi/core/pm.c > +++ b/drivers/bus/mhi/core/pm.c > @@ -1144,6 +1144,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) > mhi_deinit_dev_ctxt(mhi_cntrl); > > error_dev_ctxt: > + mhi_cntrl->pm_state = MHI_PM_DISABLE; > mutex_unlock(&mhi_cntrl->pm_mutex); > > return ret; > @@ -1155,11 +1156,17 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) > enum mhi_pm_state cur_state, transition_state; > struct device *dev = &mhi_cntrl->mhi_dev->dev; > > + mutex_lock(&mhi_cntrl->pm_mutex); > + cur_state = mhi_cntrl->pm_state; As I said in my previous review, you should use pm_lock for reading the pm_state. Thanks, Mani > + if (cur_state == MHI_PM_DISABLE) { > + mutex_unlock(&mhi_cntrl->pm_mutex); > + return; /* Already powered down */ > + } > + > /* If it's not a graceful shutdown, force MHI to linkdown state */ > transition_state = (graceful) ? MHI_PM_SHUTDOWN_PROCESS : > MHI_PM_LD_ERR_FATAL_DETECT; > > - mutex_lock(&mhi_cntrl->pm_mutex); > write_lock_irq(&mhi_cntrl->pm_lock); > cur_state = mhi_tryset_pm_state(mhi_cntrl, transition_state); > if (cur_state != transition_state) { > -- > Qualcomm Technologies, Inc. is a member of the > Code Aurora Forum, a Linux Foundation Collaborative Project. >