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=-15.2 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,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 13895C433B4 for ; Thu, 13 May 2021 02:07:20 +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 79E3961412 for ; Thu, 13 May 2021 02:07:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 79E3961412 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.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 354D36E595; Thu, 13 May 2021 02:07:18 +0000 (UTC) Received: from szxga06-in.huawei.com (szxga06-in.huawei.com [45.249.212.32]) by gabe.freedesktop.org (Postfix) with ESMTPS id 471816E595 for ; Thu, 13 May 2021 02:07:16 +0000 (UTC) Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4FgZjn4J0tzmV9g; Thu, 13 May 2021 10:05:01 +0800 (CST) Received: from [10.174.178.208] (10.174.178.208) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.498.0; Thu, 13 May 2021 10:07:09 +0800 Subject: Re: [PATCH -next] drm/panfrost: Fix PM reference leak in panfrost_job_hw_submit() To: Steven Price , , , , , References: <1620714551-106976-1-git-send-email-zou_wei@huawei.com> <7ebf35ef-58c3-7bc7-f0e9-ad487bae6686@arm.com> From: Samuel Zou Message-ID: Date: Thu, 13 May 2021 10:07:09 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <7ebf35ef-58c3-7bc7-f0e9-ad487bae6686@arm.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.178.208] X-CFilter-Loop: Reflected 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" Hi Steven, Thanks for your review and also answer my doubts. Looking forward to your patch. On 2021/5/12 23:23, Steven Price wrote: > 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; >> > > .