panic excl->shared for an AF_LOCAL socket

Hi,

PR#230752 shows a witness panic() for "excl->shared" on a vnode lock.
In this case, the kernel RPC code is trying to do a soconnect() on an AF_LOCAL
socket. The code is unp_connectat() looks like is does a straightforward
namei()/lookup(), so I am surprised to see this.

Does anyone know if AF_LOCAL (unix domain) sockets are somehow handled
differently for namei()/lookup() which might cause this?

I've requested more info from the reporter w.r.t. when this happens.
(I'd guess when the nfsuserd is terminating or has terminated or ???)

Thanks for any help with this, rick