In the Linux kernel, the following vulnerability has been resolved: dccp/tcp: Unhash sk from ehash for tb2 alloc failure after check_estalblished(). syzkaller reported a warning [0] in inet_csk_destroy_sock() with no repro. WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash); However, the syzkaller's log hinted that connect() failed just before the warning due to FAULT_INJECTION. [1] When connect() is called for an unbound socket, we search for an available ephemeral port. If a bhash bucket exists for the port, we call __inet_check_established() or __inet6_check_established() to check if the bucket is reusable. If reusable, we add the socket into ehash and set inet_sk(sk)->inet_num. Later, we look up the corresponding bhash2 bucket and try to allocate it if it does n