ACPICA: Fix NULL pointer dereference in acpi_ev_address_space_dispatch()

Cover a missed execution path with a new check.

Fixes: 0acf24ad7e10 ("ACPICA: Add support for PCC Opregion special context data")
Link: https://github.com/acpica/acpica/commit/f421dd9dd897
Signed-off-by: Alexey Simakov <bigalex934@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/3030574.e9J7NaK4W3@rafael.j.wysocki

diff --git a/drivers/acpi/acpica/evregion.c b/drivers/acpi/acpica/evregion.c
index fa3475da7ea9b670b76e7961327d75afb6c97d56..b6198f73c81dfa6d1ed0480ccc96c16ccb9801f1 100644 (file)
--- a/drivers/acpi/acpica/evregion.c
+++ b/drivers/acpi/acpica/evregion.c
@@ -163,7 +163,9 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
                        return_ACPI_STATUS(AE_NOT_EXIST);
                }
 
-               if (region_obj->region.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
+               if (field_obj
+                   && region_obj->region.space_id ==
+                   ACPI_ADR_SPACE_PLATFORM_COMM) {
                        struct acpi_pcc_info *ctx =
                            handler_desc->address_space.context;