Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 701 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/psparse.c b/drivers/acpi/acpica/psparse.c
new file mode 100644
index 000000000..42ec8abef
--- /dev/null
+++ b/drivers/acpi/acpica/psparse.c
@@ -0,0 +1,701 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/******************************************************************************
+ *
+ * Module Name: psparse - Parser top level AML parse routines
+ *
+ * Copyright (C) 2000 - 2026, Intel Corp.
+ *
+ *****************************************************************************/
+
+/*
+ * Parse the AML and build an operation tree as most interpreters,
+ * like Perl, do. Parsing is done by hand rather than with a YACC
+ * generated parser to tightly constrain stack and dynamic memory
+ * usage. At the same time, parsing is kept flexible and the code
+ * fairly compact by parsing based on a list of AML opcode
+ * templates in aml_op_info[]
+ */
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "acparser.h"
+#include "acdispat.h"
+#include "amlcode.h"
+#include "acinterp.h"
+#include "acnamesp.h"
+
+#define _COMPONENT          ACPI_PARSER
+ACPI_MODULE_NAME("psparse")
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ps_get_opcode_size
+ *
+ * PARAMETERS:  opcode          - An AML opcode
+ *
+ * RETURN:      Size of the opcode, in bytes (1 or 2)
+ *
+ * DESCRIPTION: Get the size of the current opcode.
+ *
+ ******************************************************************************/
+u32 acpi_ps_get_opcode_size(u32 opcode)
+{
+
+	/* Extended (2-byte) opcode if > 255 */
+
+	if (opcode > 0x00FF) {
+		return (2);
+	}
+
+	/* Otherwise, just a single byte opcode */
+
+	return (1);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ps_peek_opcode
+ *
+ * PARAMETERS:  parser_state        - A parser state object
+ *
+ * RETURN:      Next AML opcode
+ *
+ * DESCRIPTION: Get next AML opcode (without incrementing AML pointer)
+ *
+ ******************************************************************************/
+
+u16 acpi_ps_peek_opcode(struct acpi_parse_state * parser_state)
+{
+	u8 *aml;
+	u16 opcode;
+
+	aml = parser_state->aml;
+	if (aml >= parser_state->aml_end) {
+		return (0xFFFF);
+	}
+	opcode = (u16) ACPI_GET8(aml);
+
+	if (opcode == AML_EXTENDED_PREFIX) {
+
+		/* Extended opcode, get the second opcode byte */
+
+		aml++;
+		if (aml >= parser_state->aml_end) {
+			return (0xFFFF);
+		}
+		opcode = (u16) ((opcode << 8) | ACPI_GET8(aml));
+	}
+
+	return (opcode);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ps_complete_this_op
+ *
+ * PARAMETERS:  walk_state      - Current State
+ *              op              - Op to complete
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Perform any cleanup at the completion of an Op.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ps_complete_this_op(struct acpi_walk_state *walk_state,
+			 union acpi_parse_object *op)
+{
+	union acpi_parse_object *prev;
+	union acpi_parse_object *next;
+	const struct acpi_opcode_info *parent_info;
+	union acpi_parse_object *replacement_op = NULL;
+	acpi_status status = AE_OK;
+
+	ACPI_FUNCTION_TRACE_PTR(ps_complete_this_op, op);
+
+	/* Check for null Op, can happen if AML code is corrupt */
+
+	if (!op) {
+		return_ACPI_STATUS(AE_OK);	/* OK for now */
+	}
+
+	acpi_ex_stop_trace_opcode(op, walk_state);
+
+	/* Delete this op and the subtree below it if asked to */
+
+	if (((walk_state->parse_flags & ACPI_PARSE_TREE_MASK) !=
+	     ACPI_PARSE_DELETE_TREE)
+	    || (walk_state->op_info->class == AML_CLASS_ARGUMENT)) {
+		return_ACPI_STATUS(AE_OK);
+	}
+
+	/* Make sure that we only delete this subtree */
+
+	if (op->common.parent) {
+		prev = op->common.parent->common.value.arg;
+		if (!prev) {
+
+			/* Nothing more to do */
+
+			goto cleanup;
+		}
+
+		/*
+		 * Check if we need to replace the operator and its subtree
+		 * with a return value op (placeholder op)
+		 */
+		parent_info =
+		    acpi_ps_get_opcode_info(op->common.parent->common.
+					    aml_opcode);
+
+		switch (parent_info->class) {
+		case AML_CLASS_CONTROL:
+
+			break;
+
+		case AML_CLASS_CREATE:
+			/*
+			 * These opcodes contain term_arg operands. The current
+			 * op must be replaced by a placeholder return op
+			 */
+			replacement_op =
+			    acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP,
+					     op->common.aml);
+			if (!replacement_op) {
+				status = AE_NO_MEMORY;
+			}
+			break;
+
+		case AML_CLASS_NAMED_OBJECT:
+			/*
+			 * These opcodes contain term_arg operands. The current
+			 * op must be replaced by a placeholder return op
+			 */
+			if ((op->common.parent->common.aml_opcode ==
+			     AML_REGION_OP)
+			    || (op->common.parent->common.aml_opcode ==
+				AML_DATA_REGION_OP)
+			    || (op->common.parent->common.aml_opcode ==
+				AML_BUFFER_OP)
+			    || (op->common.parent->common.aml_opcode ==
+				AML_PACKAGE_OP)
+			    || (op->common.parent->common.aml_opcode ==
+				AML_BANK_FIELD_OP)
+			    || (op->common.parent->common.aml_opcode ==
+				AML_VARIABLE_PACKAGE_OP)) {
+				replacement_op =
+				    acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP,
+						     op->common.aml);
+				if (!replacement_op) {
+					status = AE_NO_MEMORY;
+				}
+			} else
+			    if ((op->common.parent->common.aml_opcode ==
+				 AML_NAME_OP)
+				&& (walk_state->pass_number <=
+				    ACPI_IMODE_LOAD_PASS2)) {
+				if ((op->common.aml_opcode == AML_BUFFER_OP)
+				    || (op->common.aml_opcode == AML_PACKAGE_OP)
+				    || (op->common.aml_opcode ==
+					AML_VARIABLE_PACKAGE_OP)) {
+					replacement_op =
+					    acpi_ps_alloc_op(op->common.
+							     aml_opcode,
+							     op->common.aml);
+					if (!replacement_op) {
+						status = AE_NO_MEMORY;
+					} else {
+						replacement_op->named.data =
+						    op->named.data;
+						replacement_op->named.length =
+						    op->named.length;
+					}
+				}
+			}
+			break;
+
+		default:
+
+			replacement_op =
+			    acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP,
+					     op->common.aml);
+			if (!replacement_op) {
+				status = AE_NO_MEMORY;
+			}
+		}
+
+		/* We must unlink this op from the parent tree */
+
+		if (prev == op) {
+
+			/* This op is the first in the list */
+
+			if (replacement_op) {
+				replacement_op->common.parent =
+				    op->common.parent;
+				replacement_op->common.value.arg = NULL;
+				replacement_op->common.node = op->common.node;
+				op->common.parent->common.value.arg =
+				    replacement_op;
+				replacement_op->common.next = op->common.next;
+			} else {
+				op->common.parent->common.value.arg =
+				    op->common.next;
+			}
+		}
+
+		/* Search the parent list */
+
+		else
+			while (prev) {
+
+				/* Traverse all siblings in the parent's argument list */
+
+				next = prev->common.next;
+				if (next == op) {
+					if (replacement_op) {
+						replacement_op->common.parent =
+						    op->common.parent;
+						replacement_op->common.value.
+						    arg = NULL;
+						replacement_op->common.node =
+						    op->common.node;
+						prev->common.next =
+						    replacement_op;
+						replacement_op->common.next =
+						    op->common.next;
+						next = NULL;
+					} else {
+						prev->common.next =
+						    op->common.next;
+						next = NULL;
+					}
+				}
+				prev = next;
+			}
+	}
+
+cleanup:
+
+	/* Now we can actually delete the subtree rooted at Op */
+
+	acpi_ps_delete_parse_tree(op);
+	return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ps_next_parse_state
+ *
+ * PARAMETERS:  walk_state          - Current state
+ *              op                  - Current parse op
+ *              callback_status     - Status from previous operation
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Update the parser state based upon the return exception from
+ *              the parser callback.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ps_next_parse_state(struct acpi_walk_state *walk_state,
+			 union acpi_parse_object *op,
+			 acpi_status callback_status)
+{
+	struct acpi_parse_state *parser_state = &walk_state->parser_state;
+	acpi_status status = AE_CTRL_PENDING;
+	u8 *aml;
+
+	ACPI_FUNCTION_TRACE_PTR(ps_next_parse_state, op);
+
+	switch (callback_status) {
+	case AE_CTRL_TERMINATE:
+		/*
+		 * A control method was terminated via a RETURN statement.
+		 * The walk of this method is complete.
+		 */
+		parser_state->aml = parser_state->aml_end;
+		status = AE_CTRL_TERMINATE;
+		break;
+
+	case AE_CTRL_BREAK:
+
+		parser_state->aml = walk_state->aml_last_while;
+		walk_state->control_state->common.value = FALSE;
+		status = AE_CTRL_BREAK;
+		break;
+
+	case AE_CTRL_CONTINUE:
+
+		parser_state->aml = walk_state->aml_last_while;
+		status = AE_CTRL_CONTINUE;
+		break;
+
+	case AE_CTRL_PENDING:
+
+		parser_state->aml = walk_state->aml_last_while;
+		break;
+
+#if 0
+	case AE_CTRL_SKIP:
+
+		parser_state->aml = parser_state->scope->parse_scope.pkg_end;
+		status = AE_OK;
+		break;
+#endif
+
+	case AE_CTRL_TRUE:
+		/*
+		 * Predicate of an IF was true, and we are at the matching ELSE.
+		 * Just close out this package
+		 */
+		aml = parser_state->aml;
+
+		parser_state->aml = acpi_ps_get_next_package_end(parser_state);
+		if ((parser_state->aml > parser_state->aml_end) ||
+		    (parser_state->aml < aml)) {
+			status = AE_AML_PACKAGE_LIMIT;
+			break;
+		}
+		status = AE_CTRL_PENDING;
+		break;
+
+	case AE_CTRL_FALSE:
+		/*
+		 * Either an IF/WHILE Predicate was false or we encountered a BREAK
+		 * opcode. In both cases, we do not execute the rest of the
+		 * package;  We simply close out the parent (finishing the walk of
+		 * this branch of the tree) and continue execution at the parent
+		 * level.
+		 */
+		parser_state->aml = parser_state->scope->parse_scope.pkg_end;
+
+		/* In the case of a BREAK, just force a predicate (if any) to FALSE */
+
+		walk_state->control_state->common.value = FALSE;
+		status = AE_CTRL_END;
+		break;
+
+	case AE_CTRL_TRANSFER:
+
+		/* A method call (invocation) -- transfer control */
+
+		status = AE_CTRL_TRANSFER;
+		walk_state->prev_op = op;
+		walk_state->method_call_op = op;
+		walk_state->method_call_node =
+		    (op->common.value.arg)->common.node;
+
+		/* Will return value (if any) be used by the caller? */
+
+		walk_state->return_used =
+		    acpi_ds_is_result_used(op, walk_state);
+		break;
+
+	default:
+
+		status = callback_status;
+		if (ACPI_CNTL_EXCEPTION(callback_status)) {
+			status = AE_OK;
+		}
+		break;
+	}
+
+	return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ps_parse_aml
+ *
+ * PARAMETERS:  walk_state      - Current state
+ *
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Parse raw AML and return a tree of ops
+ *
+ ******************************************************************************/
+
+acpi_status acpi_ps_parse_aml(struct acpi_walk_state *walk_state)
+{
+	acpi_status status;
+	struct acpi_thread_state *thread;
+	struct acpi_thread_state *prev_walk_list = acpi_gbl_current_walk_list;
+	struct acpi_walk_state *previous_walk_state;
+
+	ACPI_FUNCTION_TRACE(ps_parse_aml);
+
+	ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
+			  "Entered with WalkState=%p Aml=%p size=%X\n",
+			  walk_state, walk_state->parser_state.aml,
+			  walk_state->parser_state.aml_size));
+
+	if (!walk_state->parser_state.aml) {
+		return_ACPI_STATUS(AE_BAD_ADDRESS);
+	}
+
+	/* Create and initialize a new thread state */
+
+	thread = acpi_ut_create_thread_state();
+	if (!thread) {
+		if (walk_state->method_desc) {
+
+			/* Executing a control method - additional cleanup */
+
+			acpi_ds_terminate_control_method(walk_state->
+							 method_desc,
+							 walk_state);
+		}
+
+		acpi_ds_delete_walk_state(walk_state);
+		return_ACPI_STATUS(AE_NO_MEMORY);
+	}
+
+	walk_state->thread = thread;
+
+	/*
+	 * If executing a method, the starting sync_level is this method's
+	 * sync_level
+	 */
+	if (walk_state->method_desc) {
+		walk_state->thread->current_sync_level =
+		    walk_state->method_desc->method.sync_level;
+	}
+
+	acpi_ds_push_walk_state(walk_state, thread);
+
+	/*
+	 * This global allows the AML debugger to get a handle to the currently
+	 * executing control method.
+	 */
+	acpi_gbl_current_walk_list = thread;
+
+	/*
+	 * Execute the walk loop as long as there is a valid Walk State. This
+	 * handles nested control method invocations without recursion.
+	 */
+	ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "State=%p\n", walk_state));
+
+	status = AE_OK;
+	while (walk_state) {
+		if (ACPI_SUCCESS(status)) {
+			/*
+			 * The parse_loop executes AML until the method terminates
+			 * or calls another method.
+			 */
+			status = acpi_ps_parse_loop(walk_state);
+		}
+
+		ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
+				  "Completed one call to walk loop, %s State=%p\n",
+				  acpi_format_exception(status), walk_state));
+
+		if (walk_state->method_pathname && walk_state->method_is_nested) {
+
+			/* Optional object evaluation log */
+
+			ACPI_DEBUG_PRINT_RAW((ACPI_DB_EVALUATION,
+					      "%-26s:  %*s%s\n",
+					      "   Exit nested method",
+					      (walk_state->
+					       method_nesting_depth + 1) * 3,
+					      " ",
+					      &walk_state->method_pathname[1]));
+
+			ACPI_FREE(walk_state->method_pathname);
+			walk_state->method_is_nested = FALSE;
+		}
+		if (status == AE_CTRL_TRANSFER) {
+			/*
+			 * A method call was detected.
+			 * Transfer control to the called control method
+			 */
+			status =
+			    acpi_ds_call_control_method(thread, walk_state,
+							NULL);
+			if (ACPI_FAILURE(status)) {
+				status =
+				    acpi_ds_method_error(status, walk_state);
+			}
+
+			/*
+			 * If the transfer to the new method method call worked,
+			 * a new walk state was created -- get it
+			 */
+			walk_state = acpi_ds_get_current_walk_state(thread);
+			continue;
+		} else if (status == AE_CTRL_TERMINATE) {
+			status = AE_OK;
+		} else if ((status != AE_OK) && (walk_state->method_desc)) {
+
+			/* Either the method parse or actual execution failed */
+
+			acpi_ex_exit_interpreter();
+			if (status == AE_ABORT_METHOD) {
+				acpi_ns_print_node_pathname(walk_state->
+							    method_node,
+							    "Aborting method");
+				acpi_os_printf("\n");
+			} else {
+				ACPI_ERROR_METHOD("Aborting method",
+						  walk_state->method_node, NULL,
+						  status);
+			}
+			acpi_ex_enter_interpreter();
+
+			/* Check for possible multi-thread reentrancy problem */
+
+			if ((status == AE_ALREADY_EXISTS) &&
+			    (!(walk_state->method_desc->method.info_flags &
+			       ACPI_METHOD_SERIALIZED))) {
+				/*
+				 * Method is not serialized and tried to create an object
+				 * twice. The probable cause is that the method cannot
+				 * handle reentrancy. Mark as "pending serialized" now, and
+				 * then mark "serialized" when the last thread exits.
+				 */
+				walk_state->method_desc->method.info_flags |=
+				    ACPI_METHOD_SERIALIZED_PENDING;
+			}
+		}
+
+		/* We are done with this walk, move on to the parent if any */
+
+		walk_state = acpi_ds_pop_walk_state(thread);
+
+		/* Reset the current scope to the beginning of scope stack */
+
+		acpi_ds_scope_stack_clear(walk_state);
+
+		/*
+		 * If we just returned from the execution of a control method or if we
+		 * encountered an error during the method parse phase, there's lots of
+		 * cleanup to do
+		 */
+		if (((walk_state->parse_flags & ACPI_PARSE_MODE_MASK) ==
+		     ACPI_PARSE_EXECUTE &&
+		     !(walk_state->parse_flags & ACPI_PARSE_MODULE_LEVEL)) ||
+		    (ACPI_FAILURE(status))) {
+			acpi_ds_terminate_control_method(walk_state->
+							 method_desc,
+							 walk_state);
+		}
+
+		/* Delete this walk state and all linked control states */
+
+		acpi_ps_cleanup_scope(&walk_state->parser_state);
+		previous_walk_state = walk_state;
+
+		ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
+				  "ReturnValue=%p, ImplicitValue=%p State=%p\n",
+				  walk_state->return_desc,
+				  walk_state->implicit_return_obj, walk_state));
+
+		/* Check if we have restarted a preempted walk */
+
+		walk_state = acpi_ds_get_current_walk_state(thread);
+		if (walk_state) {
+			if (ACPI_SUCCESS(status)) {
+				/*
+				 * There is another walk state, restart it.
+				 * If the method return value is not used by the parent,
+				 * The object is deleted
+				 */
+				if (!previous_walk_state->return_desc) {
+					/*
+					 * In slack mode execution, if there is no return value
+					 * we should implicitly return zero (0) as a default value.
+					 */
+					if (acpi_gbl_enable_interpreter_slack &&
+					    !previous_walk_state->
+					    implicit_return_obj) {
+						previous_walk_state->
+						    implicit_return_obj =
+						    acpi_ut_create_integer_object
+						    ((u64) 0);
+						if (!previous_walk_state->
+						    implicit_return_obj) {
+							return_ACPI_STATUS
+							    (AE_NO_MEMORY);
+						}
+					}
+
+					/* Restart the calling control method */
+
+					status =
+					    acpi_ds_restart_control_method
+					    (walk_state,
+					     previous_walk_state->
+					     implicit_return_obj);
+				} else {
+					/*
+					 * We have a valid return value, delete any implicit
+					 * return value.
+					 */
+					acpi_ds_clear_implicit_return
+					    (previous_walk_state);
+
+					status =
+					    acpi_ds_restart_control_method
+					    (walk_state,
+					     previous_walk_state->return_desc);
+				}
+				if (ACPI_SUCCESS(status)) {
+					walk_state->walk_type |=
+					    ACPI_WALK_METHOD_RESTART;
+				}
+			} else {
+				/* On error, delete any return object or implicit return */
+
+				acpi_ut_remove_reference(previous_walk_state->
+							 return_desc);
+				acpi_ds_clear_implicit_return
+				    (previous_walk_state);
+			}
+		}
+
+		/*
+		 * Just completed a 1st-level method, save the final internal return
+		 * value (if any)
+		 */
+		else if (previous_walk_state->caller_return_desc) {
+			if (previous_walk_state->implicit_return_obj) {
+				*(previous_walk_state->caller_return_desc) =
+				    previous_walk_state->implicit_return_obj;
+			} else {
+				/* NULL if no return value */
+
+				*(previous_walk_state->caller_return_desc) =
+				    previous_walk_state->return_desc;
+			}
+		} else {
+			if (previous_walk_state->return_desc) {
+
+				/* Caller doesn't want it, must delete it */
+
+				acpi_ut_remove_reference(previous_walk_state->
+							 return_desc);
+			}
+			if (previous_walk_state->implicit_return_obj) {
+
+				/* Caller doesn't want it, must delete it */
+
+				acpi_ut_remove_reference(previous_walk_state->
+							 implicit_return_obj);
+			}
+		}
+
+		acpi_ds_delete_walk_state(previous_walk_state);
+	}
+
+	/* Normal exit */
+
+	acpi_ex_release_all_mutexes(thread);
+	acpi_ut_delete_generic_state(ACPI_CAST_PTR
+				     (union acpi_generic_state, thread));
+	acpi_gbl_current_walk_list = prev_walk_list;
+	return_ACPI_STATUS(status);
+}