restorer: exit all threads in case of error

sys_exit() takes down only the currect thread. exit_group() should
be used to take down all threads.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Looks-good-to: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/syscall-x86-64.def

@@ -56,6 +56,7 @@ __NR_set_thread_area	205		sys_set_thread_area	(user_desc_t *info)
 __NR_get_thread_area	211		sys_get_thread_area	(user_desc_t *info)
 __NR_set_tid_address	218		sys_set_tid_address	(int *tid_addr)
 __NR_restart_syscall	219		sys_restart_syscall	(void)
+__NR_exit_group		231		sys_exit_group		(int error_code)
 __NR_open_by_handle_at	304		sys_open_by_handle_at	(int mountdirfd, struct file_handle *handle, int flags)
 __NR_setns		308		sys_setns		(int fd, int nstype)
 __NR_kcmp		312		sys_kcmp		(pid_t pid1, pid_t pid2, int type, unsigned long idx1, unsigned long idx2)

restorer.c

@@ -47,7 +47,7 @@ static void sigchld_handler(int signal, siginfo_t *siginfo, void *data)
 	futex_abort_and_wake(&task_entries->nr_in_progress);
 	/* sa_restorer may be unmaped, so we can't go back to userspace*/
 	sys_kill(sys_getpid(), SIGSTOP);
-	sys_exit(1);
+	sys_exit_group(1);
 }
 
 static void restore_creds(struct creds_entry *ce)
@@ -226,7 +226,7 @@ long __export_restore_thread(struct thread_restore_args *args)
 core_restore_end:
 	write_num_n(__LINE__);
 	write_num_n(sys_getpid());
-	sys_exit(-1);
+	sys_exit_group(1);
 	return -1;
 }
 
@@ -687,7 +687,7 @@ long __export_restore_task(struct task_restore_core_args *args)
 core_restore_end:
 	write_num_n(__LINE__);
 	write_num_n(sys_getpid());
-	sys_exit(-1);
+	sys_exit_group(1);
 	return -1;
 
 core_restore_failed: