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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 D8138C433ED for ; Wed, 12 May 2021 15:23:53 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 76EB461CA1 for ; Wed, 12 May 2021 15:23:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 76EB461CA1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C61AE890FE; Wed, 12 May 2021 15:23:52 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id D65E0890FE for ; Wed, 12 May 2021 15:23:51 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2D06931B; Wed, 12 May 2021 08:23:51 -0700 (PDT) Received: from [192.168.1.179] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 051603F718; Wed, 12 May 2021 08:23:49 -0700 (PDT) Subject: Re: [PATCH -next] drm/panfrost: Fix PM reference leak in panfrost_job_hw_submit() To: Zou Wei , robh@kernel.org, tomeu.vizoso@collabora.com, airlied@linux.ie, daniel@ffwll.ch, alyssa.rosenzweig@collabora.com References: <1620714551-106976-1-git-send-email-zou_wei@huawei.com> From: Steven Price Message-ID: <7ebf35ef-58c3-7bc7-f0e9-ad487bae6686@arm.com> Date: Wed, 12 May 2021 16:23:48 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <1620714551-106976-1-git-send-email-zou_wei@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 11/05/2021 07:29, Zou Wei wrote: > pm_runtime_get_sync will increment pm usage counter even it failed. > Forgetting to putting operation will result in reference leak here. > Fix it by replacing it with pm_runtime_resume_and_get to keep usage > counter balanced. > > Reported-by: Hulk Robot > Signed-off-by: Zou Wei Thanks for the patch, but this is actually incorrect. panfrost_job_hw_submit() is expected to unconditionally increment the pm usage counter. This is because panfrost_job_hw_submit() can (currently) never fail, so in this case the job is considered "submitted" (even though it never reaches the hardware) and it's handled by the job timeout. However this is at least the second time[1] this phantom "reference leak" has been raised, so perhaps it's time to handle this better. I'll post a patch reworking panfrost_job_hw_submit() so it can fail. Thanks, Steve [1] https://lore.kernel.org/r/20200520110504.24388-1-dinghao.liu%40zju.edu.cn > --- > drivers/gpu/drm/panfrost/panfrost_job.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c > index 6003cfe..42d8dbc 100644 > --- a/drivers/gpu/drm/panfrost/panfrost_job.c > +++ b/drivers/gpu/drm/panfrost/panfrost_job.c > @@ -157,7 +157,7 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js) > > panfrost_devfreq_record_busy(&pfdev->pfdevfreq); > > - ret = pm_runtime_get_sync(pfdev->dev); > + ret = pm_runtime_resume_and_get(pfdev->dev); > if (ret < 0) > return; > >