linux-kernel - [PATCH] drm/gma500: Fix null dereference in hdmi teardown

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Message-ID: <20250918150703.2562604-1-n.zabelin@mt-integration.ru>
Date: Thu, 18 Sep 2025 18:06:59 +0300
From: Zabelin Nikita <n.zabelin@...integration.ru>
To: Patrik Jakobsson <patrik.r.jakobsson@...il.com>
CC: Zabelin Nikita <n.zabelin@...integration.ru>, David Airlie
	<airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>, Dave Airlie
	<airlied@...hat.com>, Alan Cox <alan@...ux.intel.com>,
	<dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
	<lvc-project@...uxtesting.org>
Subject: [PATCH] drm/gma500: Fix null dereference in hdmi teardown

pci_set_drvdata sets the value of pdev->driver_data to NULL,
after which the driver_data obtained from the same dev is 
dereferenced in oaktrail_hdmi_i2c_exit, and the i2c_dev is 
extracted from it. To prevent this, swap these calls.

Fixes: 1b082cc ("gma500: Add Oaktrail support")

Found by Linux Verification Center (linuxtesting.org) with Svacer.

Signed-off-by: Zabelin Nikita <n.zabelin@...integration.ru>
---
 drivers/gpu/drm/gma500/oaktrail_hdmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/gma500/oaktrail_hdmi.c b/drivers/gpu/drm/gma500/oaktrail_hdmi.c
index 95b7cb099e63..9c7d9584aac7 100644
--- a/drivers/gpu/drm/gma500/oaktrail_hdmi.c
+++ b/drivers/gpu/drm/gma500/oaktrail_hdmi.c
@@ -724,8 +724,8 @@ void oaktrail_hdmi_teardown(struct drm_device *dev)
 
 	if (hdmi_dev) {
 		pdev = hdmi_dev->dev;
-		pci_set_drvdata(pdev, NULL);
 		oaktrail_hdmi_i2c_exit(pdev);
+		pci_set_drvdata(pdev, NULL);
 		iounmap(hdmi_dev->regs);
 		kfree(hdmi_dev);
 		pci_dev_put(pdev);
-- 
2.43.0