4.19-stable review patch. If anyone has any objections, please let me know.
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From: Nikita Kiryushin kiryushin@ancud.ru
[ 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: 9661e92c10a9 ("acpi: tie ACPI backlight devices to PCI devices if possible") Signed-off-by: Nikita Kiryushin kiryushin@ancud.ru Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/acpi/acpi_video.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c index eb7fca6f9444..c22297cce288 100644 --- a/drivers/acpi/acpi_video.c +++ b/drivers/acpi/acpi_video.c @@ -1797,12 +1797,12 @@ static void acpi_video_dev_register_backlight(struct acpi_video_device *device) return; count++;
- acpi_get_parent(device->dev->handle, &acpi_parent); - - pdev = acpi_get_pci_dev(acpi_parent); - if (pdev) { - parent = &pdev->dev; - pci_dev_put(pdev); + 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));