ACPICA commit 
0dd68e16274cd38224aa4781eddc57dc2cbaa108
The quit/exit commands shouldn't invoke acpi_terminate_debugger() and
acpi_terminate() right in the user command loop, because when the debugger
exits, the kernel ACPI subsystem shouldn't be terminated (acpi_terminate())
and the debugger should only be terminated by its users
(acpi_terminate_debugger()) rather than being terminated itself. Leaving such
invocations causes kernel panic when the debugger is shipped in the Linux
kernel.
This patch fixes this issue. Lv Zheng.
Link: https://github.com/acpica/acpica/commit/0dd68e16
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 
 #ifdef ACPI_DEBUGGER
 
-ACPI_INIT_GLOBAL(u8, acpi_gbl_db_terminate_threads, FALSE);
 ACPI_INIT_GLOBAL(u8, acpi_gbl_abort_method, FALSE);
 ACPI_INIT_GLOBAL(u8, acpi_gbl_method_executing, FALSE);
 
 ACPI_GLOBAL(u32, acpi_gbl_db_debug_level);
 ACPI_GLOBAL(u32, acpi_gbl_db_console_debug_level);
 ACPI_GLOBAL(struct acpi_namespace_node *, acpi_gbl_db_scope_node);
+ACPI_GLOBAL(u8, acpi_gbl_db_terminate_loop);
+ACPI_GLOBAL(u8, acpi_gbl_db_threads_terminated);
 
 ACPI_GLOBAL(char *, acpi_gbl_db_args[ACPI_DEBUGGER_MAX_ARGS]);
 ACPI_GLOBAL(acpi_object_type, acpi_gbl_db_arg_types[ACPI_DEBUGGER_MAX_ARGS]);
 
 
        /* If acpi_terminate has been called, terminate this thread */
 
-       if (acpi_gbl_db_terminate_threads) {
+       if (acpi_gbl_db_terminate_loop) {
                return (AE_CTRL_TERMINATE);
        }
 
 #ifdef ACPI_APPLICATION
                acpi_db_close_debug_file();
 #endif
-               acpi_gbl_db_terminate_threads = TRUE;
+               acpi_gbl_db_terminate_loop = TRUE;
                return (AE_CTRL_TERMINATE);
 
        case CMD_NOT_FOUND:
 
                acpi_os_release_mutex(acpi_gbl_db_command_complete);
        }
+       acpi_gbl_db_threads_terminated = TRUE;
 }
 
 /*******************************************************************************
 
        /* TBD: [Restructure] Need a separate command line buffer for step mode */
 
-       while (!acpi_gbl_db_terminate_threads) {
+       while (!acpi_gbl_db_terminate_loop) {
 
                /* Force output to console until a command is entered */
 
                }
        }
 
-       /* Shut down the debugger */
-
-       acpi_terminate_debugger();
-
-       /*
-        * Only this thread (the original thread) should actually terminate the
-        * subsystem, because all the semaphores are deleted during termination
-        */
-       status = acpi_terminate();
        return (status);
 }
 
        acpi_gbl_db_scope_buf[1] = 0;
        acpi_gbl_db_scope_node = acpi_gbl_root_node;
 
+       /* Initialize user commands loop */
+
+       acpi_gbl_db_terminate_loop = FALSE;
+
        /*
         * If configured for multi-thread support, the debug executor runs in
         * a separate thread so that the front end can be in another address
 
                /* Create the debug execution thread to execute commands */
 
+               acpi_gbl_db_threads_terminated = FALSE;
                status = acpi_os_execute(OSL_DEBUGGER_THREAD,
                                         acpi_db_execute_thread, NULL);
                if (ACPI_FAILURE(status)) {
                        ACPI_EXCEPTION((AE_INFO, status,
                                        "Could not start debugger thread"));
+                       acpi_gbl_db_threads_terminated = TRUE;
                        return_ACPI_STATUS(status);
                }
        }
 void acpi_terminate_debugger(void)
 {
 
+       /* Terminate the AML Debugger */
+
+       acpi_gbl_db_terminate_loop = TRUE;
+
+       if (acpi_gbl_debugger_configuration & DEBUGGER_MULTI_THREADED) {
+               acpi_os_release_mutex(acpi_gbl_db_command_ready);
+
+               /* Wait the AML Debugger threads */
+
+               while (!acpi_gbl_db_threads_terminated) {
+                       acpi_os_sleep(100);
+               }
+       }
+
        if (acpi_gbl_db_buffer) {
                acpi_os_free(acpi_gbl_db_buffer);
                acpi_gbl_db_buffer = NULL;
 
        acpi_gbl_disable_mem_tracking = FALSE;
 #endif
 
-       ACPI_DEBUGGER_EXEC(acpi_gbl_db_terminate_threads = FALSE);
-
        return_ACPI_STATUS(AE_OK);
 }
 
 
        acpi_gbl_startup_flags = 0;
        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Shutting down ACPI Subsystem\n"));
 
-       /* Terminate the AML Debugger if present */
-
-       ACPI_DEBUGGER_EXEC(acpi_gbl_db_terminate_threads = TRUE);
-
        /* Shutdown and free all resources */
 
        acpi_ut_subsystem_shutdown();