In the Linux kernel, the following vulnerability has been resolved:vsock/bpf: return early if transport is not assignedSome of the core functions can only be called if the transport
has been assigned.As Michal reported, a socket might have the transport at NULL,
for example after a failed connect(), causing the following trace:So we need to check the `vsk->transport` in vsock_bpf_recvmsg(),
especially for connected sockets (stream/seqpacket) as we already
do in __vsock_connectible_recvmsg().