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Commit 1e3a2b9b authored by Nikita Kiryushin's avatar Nikita Kiryushin Committed by Greg Kroah-Hartman
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ACPI: video: check for error while searching for backlight device parent 



[ Upstream commit ccd45faf4973746c4f30ea41eec864e5cf191099 ]

If acpi_get_parent() called in acpi_video_dev_register_backlight()
fails, for example, because acpi_ut_acquire_mutex() fails inside
acpi_get_parent), this can lead to incorrect (uninitialized)
acpi_parent handle being passed to acpi_get_pci_dev() for detecting
the parent pci device.

Check acpi_get_parent() result and set parent device only in case of success.

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

Fixes: 9661e92c ("acpi: tie ACPI backlight devices to PCI devices if possible")
Signed-off-by: default avatarNikita Kiryushin <kiryushin@ancud.ru>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent f5ea2cf3

drivers/acpi/acpi_video.c

+6 −6
Original line number Diff line number Diff line
@@ -1784,13 +1784,13 @@ static void acpi_video_dev_register_backlight(struct acpi_video_device *device) 
		return;

	count++;



	acpi_get_parent(device->dev->handle, &acpi_parent);



	if (ACPI_SUCCESS(acpi_get_parent(device->dev->handle, &acpi_parent))) {

		pdev = acpi_get_pci_dev(acpi_parent);

		if (pdev) {

			parent = &pdev->dev;

			pci_dev_put(pdev);

		}

	}



	memset(&props, 0, sizeof(struct backlight_properties));

	props.type = BACKLIGHT_FIRMWARE;