Lemma lset_range_perm m (tp : jstate ge) b ofs (compat : mem_compatible tp m) (Efind : AMap.find (elt:=option rmap) (b, ofs) (lset tp) <> None) : Mem.range_perm (restrPermMap (mem_compatible_locks_ltwritable compat)) b ofs (ofs + LKSIZE) Cur Writable.