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=-15.8 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 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 C2909C433ED for ; Mon, 17 May 2021 09:27:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2EAF61260 for ; Mon, 17 May 2021 09:27:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235971AbhEQJ3K (ORCPT ); Mon, 17 May 2021 05:29:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235544AbhEQJ3G (ORCPT ); Mon, 17 May 2021 05:29:06 -0400 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 71709C061573 for ; Mon, 17 May 2021 02:27:50 -0700 (PDT) Received: by mail-pj1-x1029.google.com with SMTP id b13-20020a17090a8c8db029015cd97baea9so4214513pjo.0 for ; Mon, 17 May 2021 02:27:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ZwRMoqcaR++/qsLAMyEgC+MY+iTWFtr0y91F+kn7q8k=; b=Z8swXdkk+dKfh+aLLxhLi8lWlp4mkbfMy/81Cjd4MDnE64ZghW9ZueJEk6L84nQFA6 krBrRuJPLVECGL2IL+Pf+70BMzd2l9DshYECpaD+MbqUho81FRck40Nf9k9R2ifYg4Zc k4evgSLsNrwHG6f5yfnZu+YwptE5N7AGmXlBTk1135zokyikVgbHGlT6XbVOJK/5oyTZ FoCiPmAEIMuS9CMOZJg5CaNe8QYbxV8zkeAcbJLI+H+jXju78FuAwBGLhNYbRvmo2cnN Q3uNMB4x8bi45RqbF55ZR1ZcG9eETFmNpYRbrY41TsFGjDtY/NzK+GZhbi2MwfSABUwi CkMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ZwRMoqcaR++/qsLAMyEgC+MY+iTWFtr0y91F+kn7q8k=; b=qMWs+ISfcbrILpL2tEWrOzauvsmFGzt2PfN6qhZ5TWy0XeXfk6OHNP4NlKRR6onHNV L1VLkC3srIQ8UIjWyLrFfYKdW6n3oF97Nls0f83izC2poflpEWuMiTTir+L6/4pkdmBI ZzwQrO92MMb+Gvl3CFLgfjnvfu1G/IuU2sZLftIptFJaZFfbBX16Z49ejq86iLbHbrnQ wf+CTWlCS1F6kXHNHo4PT7NzvV0BG094nahQ1HUc9j60EBWjk7zacN96PPMvph48S/8e 4NUjgg2K7dDVtcKHG98EZAST9GLfSs6HfBn8/rE3SYroDKEIsIFzeMxKK2YY0c0NrnZs e+/g== X-Gm-Message-State: AOAM533juN406KVPP28Pxd8a/pLIjJpP/l2u+jRSjlL7EQWvXECG7ado XTbLCDvNSUD59jAqXgJMh2fVtQ36mFqmafN2Bf4HZA== X-Google-Smtp-Source: ABdhPJydTvFkg9dPdtjhuUxgGffLzT1pa4jhJl8umCT+4dwADgxZnkhU5/LAv8lw46BvzqEzkVDm+zHeE9Ii18tTSYg= X-Received: by 2002:a17:902:4:b029:ee:8f40:ecbf with SMTP id 4-20020a1709020004b02900ee8f40ecbfmr58725953pla.28.1621243669932; Mon, 17 May 2021 02:27:49 -0700 (PDT) MIME-Version: 1.0 References: <20210517081601.1563193-1-yukuai3@huawei.com> In-Reply-To: <20210517081601.1563193-1-yukuai3@huawei.com> From: Robert Foss Date: Mon, 17 May 2021 11:27:38 +0200 Message-ID: Subject: Re: [PATCH] drm: bridge: cdns-mhdp8546: Fix PM reference leak in cdns_mhdp_probe() To: Yu Kuai Cc: Andrzej Hajda , Neil Armstrong , David Airlie , Daniel Vetter , dri-devel , linux-kernel , yi.zhang@huawei.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey Yu, On Mon, 17 May 2021 at 10:08, Yu Kuai 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: Yu Kuai > --- > drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > index 0cd8f40fb690..305489d48c16 100644 > --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > @@ -2478,7 +2478,7 @@ static int cdns_mhdp_probe(struct platform_device *pdev) > clk_prepare_enable(clk); > > pm_runtime_enable(dev); > - ret = pm_runtime_get_sync(dev); > + ret = pm_runtime_resume_and_get(dev); > if (ret < 0) { > dev_err(dev, "pm_runtime_get_sync failed\n"); > pm_runtime_disable(dev); The code is correct as it is. If pm_runtime_get_sync() fails and increments[1] the pm.usage_count variable, that isn't a problem since pm_runtime_disable() disables pm, and resets pm.usage_count variable to zero[2]. [1] https://elixir.bootlin.com/linux/latest/source/include/linux/pm_runtime.h#L384 [2] https://elixir.bootlin.com/linux/latest/source/drivers/base/power/runtime.c#L1383 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 86844C433ED for ; Mon, 17 May 2021 09:27:53 +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 23879601FC for ; 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Mon, 17 May 2021 02:27:49 -0700 (PDT) MIME-Version: 1.0 References: <20210517081601.1563193-1-yukuai3@huawei.com> In-Reply-To: <20210517081601.1563193-1-yukuai3@huawei.com> From: Robert Foss Date: Mon, 17 May 2021 11:27:38 +0200 Message-ID: Subject: Re: [PATCH] drm: bridge: cdns-mhdp8546: Fix PM reference leak in cdns_mhdp_probe() To: Yu Kuai Content-Type: text/plain; charset="UTF-8" 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: Neil Armstrong , David Airlie , yi.zhang@huawei.com, linux-kernel , dri-devel , Andrzej Hajda Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hey Yu, On Mon, 17 May 2021 at 10:08, Yu Kuai 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: Yu Kuai > --- > drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > index 0cd8f40fb690..305489d48c16 100644 > --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > @@ -2478,7 +2478,7 @@ static int cdns_mhdp_probe(struct platform_device *pdev) > clk_prepare_enable(clk); > > pm_runtime_enable(dev); > - ret = pm_runtime_get_sync(dev); > + ret = pm_runtime_resume_and_get(dev); > if (ret < 0) { > dev_err(dev, "pm_runtime_get_sync failed\n"); > pm_runtime_disable(dev); The code is correct as it is. If pm_runtime_get_sync() fails and increments[1] the pm.usage_count variable, that isn't a problem since pm_runtime_disable() disables pm, and resets pm.usage_count variable to zero[2]. [1] https://elixir.bootlin.com/linux/latest/source/include/linux/pm_runtime.h#L384 [2] https://elixir.bootlin.com/linux/latest/source/drivers/base/power/runtime.c#L1383