On Tue, May 26, 2026 at 10:43:56AM +0000, Raf Dickson wrote:
When vmci_transport_recv_connecting_server() returns an error, vmci_transport_recv_listen() calls vsock_remove_pending() but never calls sk_acceptq_removed(). This leaves sk_ack_backlog incremented permanently.Repeated handshake failures (malformed packets, queue pair alloc failure, event subscribe failure) cause sk_ack_backlog to climb toward sk_max_ack_backlog. Once it reaches the limit the listener permanently refuses all new connections with -ECONNREFUSED, a silent denial of service requiring a process restart to recover. The two existing sk_acceptq_removed() calls in af_vsock.c do not cover this path: line 764 checks vsock_is_pending() which returns false after vsock_remove_pending(), and line 1889 is only reached on successful accept(). Fix by balancing sk_acceptq_added() with sk_acceptq_removed() on the error path. Fixes: d021c344051a ("VSOCK: Introduce VM Sockets") Cc: [email protected] Signed-off-by: Raf Dickson <[email protected]> --- net/vmw_vsock/vmci_transport.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
Acked-by: Stefano Garzarella <[email protected]>
