linux-kernel - [PATCH v2] gpu: cdns-mhdp8546: fix call balance of mhdp->clk handling routines

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250213112801.1611525-1-mordan@ispras.ru>
Date: Thu, 13 Feb 2025 14:28:01 +0300
From: Vitalii Mordan <mordan@...ras.ru>
To: Andrzej Hajda <andrzej.hajda@...el.com>
Cc: Vitalii Mordan <mordan@...ras.ru>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Robert Foss <rfoss@...nel.org>,
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
	Jonas Karlman <jonas@...boo.se>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Sui Jingfeng <sui.jingfeng@...ux.dev>,
	Aleksandr Mishin <amishin@...rgos.ru>,
	Al Viro <viro@...iv.linux.org.uk>,
	Tomi Valkeinen <tomi.valkeinen@...com>,
	Jyri Sarha <jsarha@...com>,
	Quentin Schulz <quentin.schulz@...e-electrons.com>,
	Swapnil Jakhade <sjakhade@...ence.com>,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	Fedor Pchelkin <pchelkin@...ras.ru>,
	Alexey Khoroshilov <khoroshilov@...ras.ru>,
	Vadim Mutilin <mutilin@...ras.ru>,
	lvc-project@...uxtesting.org
Subject: [PATCH v2] gpu: cdns-mhdp8546: fix call balance of mhdp->clk handling routines

If the clock mhdp->clk was not enabled in cdns_mhdp_probe(), it should not
be disabled in any path.

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 <mordan@...ras.ru>
---
v2: Use devm_clk_get_enabled() helper function, as per Dmitry Baryshkov's
request.

 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[] = {
-- 
2.25.1