This is a note to let you know that I've just added the patch titled ACPICA: Avoid walking the ACPI Namespace if it is not there to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: acpica-avoid-walking-the-acpi-namespace-if-it-is-not.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 6cbc2bca9ba2d0ef060ebb5de39a0b29f25f332a Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Date: Mon Mar 7 20:28:26 2022 +0100 ACPICA: Avoid walking the ACPI Namespace if it is not there [ Upstream commit 0c9992315e738e7d6e927ef36839a466b080dba6 ] ACPICA commit b1c3656ef4950098e530be68d4b589584f06cddc Prevent acpi_ns_walk_namespace() from crashing when called with start_node equal to ACPI_ROOT_OBJECT if the Namespace has not been instantiated yet and acpi_gbl_root_node is NULL. For instance, this can happen if the kernel is run with "acpi=off" in the command line. Link: https://github.com/acpica/acpica/commit/b1c3656ef4950098e530be68d4b589584f06cddc Link: https://lore.kernel.org/linux-acpi/CAJZ5v0hJWW_vZ3wwajE7xT38aWjY7cZyvqMJpXHzUL98-SiCVQ@xxxxxxxxxxxxxx/ Reported-by: Hans de Goede <hdegoede@xxxxxxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/acpi/acpica/nswalk.c b/drivers/acpi/acpica/nswalk.c index 915c2433463d..e7c30ce06e18 100644 --- a/drivers/acpi/acpica/nswalk.c +++ b/drivers/acpi/acpica/nswalk.c @@ -169,6 +169,9 @@ acpi_ns_walk_namespace(acpi_object_type type, if (start_node == ACPI_ROOT_OBJECT) { start_node = acpi_gbl_root_node; + if (!start_node) { + return_ACPI_STATUS(AE_NO_NAMESPACE); + } } /* Null child means "get first node" */