diff --git a/sys/sys/filedesc.h b/sys/sys/filedesc.h
index bf416e91edff..41106f7bcd44 100644
--- a/sys/sys/filedesc.h
+++ b/sys/sys/filedesc.h
@@ -141,7 +141,7 @@ static __inline struct file *
 fget_locked(struct filedesc *fdp, int fd)
 {
 
-	return ((unsigned int)fd >= fdp->fd_nfiles ? NULL : fdp->fd_ofiles[fd]);
+	return (fd < 0 || fd >= fdp->fd_nfiles ? NULL : fdp->fd_ofiles[fd]);
 }
 
 #endif /* _KERNEL */