diff --git a/net/unix/garbage.c b/net/unix/garbage.c index 7b326582d97d..85c6f05c0fa3 100644 --- a/net/unix/garbage.c +++ b/net/unix/garbage.c @@ -235,11 +235,22 @@ void unix_gc(void) * receive queues. Other, non candidate sockets _can_ be * added to queue, so we must make sure only to touch * candidates. + * + * Embryos, though never candidates themselves, affect which + * candidates are reachable by the garbage collector. Before + * being added to a listener's queue, an embryo may already + * receive data carrying SCM_RIGHTS, potentially making the + * passed socket a candidate that is not yet reachable by the + * collector. It becomes reachable once the embryo is + * enqueued. Therefore, we must ensure that no SCM-laden + * embryo appears in a (candidate) listener's queue between + * consecutive scan_children() calls. */ list_for_each_entry_safe(u, next, &gc_inflight_list, link) { + struct sock *sk = &u->sk; long total_refs; - total_refs = file_count(u->sk.sk_socket->file); + total_refs = file_count(sk->sk_socket->file); BUG_ON(!u->inflight); BUG_ON(total_refs < u->inflight); @@ -247,6 +258,11 @@ void unix_gc(void) list_move_tail(&u->link, &gc_candidates); __set_bit(UNIX_GC_CANDIDATE, &u->gc_flags); __set_bit(UNIX_GC_MAYBE_CYCLE, &u->gc_flags); + + if (sk->sk_state == TCP_LISTEN) { + unix_state_lock(sk); + unix_state_unlock(sk); + } } }