From df9271d69f4016c1169699de9a826745688103bd Mon Sep 17 00:00:00 2001
From: Erik Schmauss <erik.schmauss@intel.com>
Date: Mon, 8 Apr 2019 13:42:29 -0700
Subject: [PATCH] ACPICA: Namespace: add check to avoid null pointer
 dereference

ACPICA commit 7586a625f9c34c3169efd88470192bf63119e31a

Some ACPICA userspace tools call acpi_ut_subsystem_shutdown() during
cleanup and dereference a null pointer when cleaning up the
namespace.

Link: https://github.com/acpica/acpica/commit/7586a625
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/acpica/nsalloc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/acpi/acpica/nsalloc.c b/drivers/acpi/acpica/nsalloc.c
index 5470213b8e64..6eb63db72249 100644
--- a/drivers/acpi/acpica/nsalloc.c
+++ b/drivers/acpi/acpica/nsalloc.c
@@ -74,6 +74,10 @@ void acpi_ns_delete_node(struct acpi_namespace_node *node)
 
 	ACPI_FUNCTION_NAME(ns_delete_node);
 
+	if (!node) {
+		return_VOID;
+	}
+
 	/* Detach an object if there is one */
 
 	acpi_ns_detach_object(node);