From patchwork Fri Feb 14 15:46:32 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitalii Mordan X-Patchwork-Id: 13975167 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id DFE0FC02198 for ; Fri, 14 Feb 2025 15:46:47 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6051810ECF7; Fri, 14 Feb 2025 15:46:47 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=ispras.ru header.i=@ispras.ru header.b="J68A/g/H"; dkim-atps=neutral Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by gabe.freedesktop.org (Postfix) with ESMTPS id 125D310ECF9 for ; Fri, 14 Feb 2025 15:46:44 +0000 (UTC) Received: from ldvnode.intra.ispras.ru (unknown [10.10.2.153]) by mail.ispras.ru (Postfix) with ESMTPSA id CE13E4226E0A; Fri, 14 Feb 2025 15:46:41 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru CE13E4226E0A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1739548002; bh=azVYvGz+zR2oKDiD/DHCe0Eo9mX8jFNm8KX4oYrPrRo=; h=From:To:Cc:Subject:Date:From; b=J68A/g/HyyWGs0HPXgkWck26xQCEVyt1oVxs37MgcYDLbpM3o9mTv7RdOlT8fyY3i hxCNCq/NPT171or0snH649bTlP20UIYSdZBzuUfSsAZXUWjV+8YELxjDzYcd1+R1qX yduYt6JJ2C+BhBWpVwNi4UziVZTc+0fcq4dC2tIg= From: Vitalii Mordan To: Andrzej Hajda Cc: Vitalii Mordan , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Sui Jingfeng , Aleksandr Mishin , Al Viro , Tomi Valkeinen , Jyri Sarha , Quentin Schulz , Swapnil Jakhade , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Fedor Pchelkin , Alexey Khoroshilov , Vadim Mutilin , lvc-project@linuxtesting.org Subject: [PATCH v3] gpu: cdns-mhdp8546: fix call balance of mhdp->clk handling routines Date: Fri, 14 Feb 2025 18:46:32 +0300 Message-Id: <20250214154632.1907425-1-mordan@ispras.ru> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" If the clock mhdp->clk was not enabled in cdns_mhdp_probe(), it should not be disabled in any path. The return value of clk_prepare_enable() is not checked. If mhdp->clk was not enabled, it may be disabled in the error path of cdns_mhdp_probe() (e.g., if cdns_mhdp_load_firmware() fails) or in cdns_mhdp_remove() after a successful cdns_mhdp_probe() call. Use the devm_clk_get_enabled() helper function to ensure proper call balance for mhdp->clk. Found by Linux Verification Center (linuxtesting.org) with Klever. Fixes: fb43aa0acdfd ("drm: bridge: Add support for Cadence MHDP8546 DPI/DP bridge") Signed-off-by: Vitalii Mordan Reviewed-by: Dmitry Baryshkov --- v2: Use devm_clk_get_enabled() helper function, as per Dmitry Baryshkov's request. v3: Describe the paths that lead to unbalanced clock handling routines, as requested by Dmitry Baryshkov drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c index d081850e3c03..d4e4f484cbe5 100644 --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c @@ -2463,9 +2463,9 @@ static int cdns_mhdp_probe(struct platform_device *pdev) if (!mhdp) return -ENOMEM; - clk = devm_clk_get(dev, NULL); + clk = devm_clk_get_enabled(dev, NULL); if (IS_ERR(clk)) { - dev_err(dev, "couldn't get clk: %ld\n", PTR_ERR(clk)); + dev_err(dev, "couldn't get and enable clk: %ld\n", PTR_ERR(clk)); return PTR_ERR(clk); } @@ -2504,14 +2504,12 @@ static int cdns_mhdp_probe(struct platform_device *pdev) mhdp->info = of_device_get_match_data(dev); - clk_prepare_enable(clk); - pm_runtime_enable(dev); ret = pm_runtime_resume_and_get(dev); if (ret < 0) { dev_err(dev, "pm_runtime_resume_and_get failed\n"); pm_runtime_disable(dev); - goto clk_disable; + return ret; } if (mhdp->info && mhdp->info->ops && mhdp->info->ops->init) { @@ -2590,8 +2588,6 @@ static int cdns_mhdp_probe(struct platform_device *pdev) runtime_put: pm_runtime_put_sync(dev); pm_runtime_disable(dev); -clk_disable: - clk_disable_unprepare(mhdp->clk); return ret; } @@ -2632,8 +2628,6 @@ static void cdns_mhdp_remove(struct platform_device *pdev) cancel_work_sync(&mhdp->modeset_retry_work); flush_work(&mhdp->hpd_work); /* Ignoring mhdp->hdcp.check_work and mhdp->hdcp.prop_work here. */ - - clk_disable_unprepare(mhdp->clk); } static const struct of_device_id mhdp_ids[] = {