ACPICA: Fixed a problem with CopyObject used in conjunction with the Index operator

The reference was incorrectly dereferenced before the copy. The
reference is now correctly copied.

http://bugzilla.kernel.org/show_bug.cgi?id=5391

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/drivers/acpi/executer/exresolv.c b/drivers/acpi/executer/exresolv.c
index 795ec8c7363c..9c3cdf61dc34 100644
--- a/drivers/acpi/executer/exresolv.c
+++ b/drivers/acpi/executer/exresolv.c
@@ -189,21 +189,25 @@ acpi_ex_resolve_object_to_value(union acpi_operand_object **stack_ptr,
                         switch (stack_desc->reference.target_type) {
                         case ACPI_TYPE_BUFFER_FIELD:
 
-                                /* Just return - leave the Reference on the stack */
+                                /* Just return - do not dereference */
                                 break;
 
                         case ACPI_TYPE_PACKAGE:
 
-                                /* If method call - leave the Reference on the stack */
+                                /* If method call or copy_object - do not dereference */
 
-                                if (walk_state->opcode == AML_INT_METHODCALL_OP) {
+                                if ((walk_state->opcode ==
+                                     AML_INT_METHODCALL_OP)
+                                    || (walk_state->opcode == AML_COPY_OP)) {
                                         break;
                                 }
 
+                                /* Otherwise, dereference the package_index to a package element */
+
                                 obj_desc = *stack_desc->reference.where;
                                 if (obj_desc) {
                                         /*
-                                         * Valid obj descriptor, copy pointer to return value
+                                         * Valid object descriptor, copy pointer to return value
                                          * (i.e., dereference the package index)
                                          * Delete the ref object, increment the returned object
                                          */
@@ -212,7 +216,7 @@ acpi_ex_resolve_object_to_value(union acpi_operand_object **stack_ptr,
                                         *stack_ptr = obj_desc;
                                 } else {
                                         /*
-                                         * A NULL object descriptor means an unitialized element of
+                                         * A NULL object descriptor means an uninitialized element of
                                          * the package, can't dereference it
                                          */
                                         ACPI_ERROR((AE_INFO,
@@ -239,7 +243,7 @@ acpi_ex_resolve_object_to_value(union acpi_operand_object **stack_ptr,
                 case AML_DEBUG_OP:
                 case AML_LOAD_OP:
 
-                        /* Just leave the object as-is */
+                        /* Just leave the object as-is, do not dereference */
 
                         break;