From: Nikita Kiryushin Date: Thu, 9 Nov 2023 13:49:25 +0000 (+0300) Subject: ACPI: video: check for error while searching for backlight device parent X-Git-Tag: v5.15.148~294 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3a370502a5681986f9828e43be75ce26c6ab24af;p=thirdparty%2Fkernel%2Fstable.git 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: 9661e92c10a9 ("acpi: tie ACPI backlight devices to PCI devices if possible") Signed-off-by: Nikita Kiryushin Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c index 2b18b51f6351e..61bcdc75bee70 100644 --- a/drivers/acpi/acpi_video.c +++ b/drivers/acpi/acpi_video.c @@ -1793,12 +1793,12 @@ 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));