tools/lguest: Don't bork the terminal in case of wrong args

Running lguest without arguments or with a wrong argument name
borks the terminal, because the cleanup handler is set up too late
in the initialization process.
Signed-off-by: NDaniel Baluta <daniel.baluta@intel.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

tools/lguest/lguest.c

@@ -3266,6 +3266,9 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	/* If we exit via err(), this kills all the threads, restores tty. */
+	atexit(cleanup_devices);
+
 	/* We always have a console device, and it's always device 1. */
 	setup_console();
 
@@ -3369,9 +3372,6 @@ int main(int argc, char *argv[])
 	/* Ensure that we terminate if a device-servicing child dies. */
 	signal(SIGCHLD, kill_launcher);
 
-	/* If we exit via err(), this kills all the threads, restores tty. */
-	atexit(cleanup_devices);
-
 	/* If requested, chroot to a directory */
 	if (chroot_path) {
 		if (chroot(chroot_path) != 0)