Hi, On 3/10/26 10:18 AM, Paolo Abeni wrote: > This is an AI-generated review of your patch. The human sending this > email has considered the AI review valid, or at least plausible. > > For local reproduction steps see > https://netdev-ai.bots.linux.dev/ai-local.html > --- >> @@ -581,11 +585,21 @@ int vsock_assign_transport(struct vsock_sock *vsk, >> struct vsock_sock *psk) >> case SOCK_SEQPACKET: >> if (vsock_use_local_transport(remote_cid)) >> new_transport = transport_local; >> - else if (remote_cid <= VMADDR_CID_HOST || !transport_h2g || >> + else if (remote_cid <= VMADDR_CID_HOST || >> (remote_flags & VMADDR_FLAG_TO_HOST)) >> new_transport = transport_g2h; >> - else >> + else if (transport_h2g && >> + (!transport_h2g->has_remote_cid || >> + transport_h2g->has_remote_cid(vsk, remote_cid))) >> + new_transport = transport_h2g; >> + else if (sock_net(sk)->vsock.g2h_fallback && >> + transport_g2h && transport_g2h->has_remote_cid && >> + transport_g2h->has_remote_cid(vsk, remote_cid)) { >> + vsk->remote_addr.svm_flags |= VMADDR_FLAG_TO_HOST; >> + new_transport = transport_g2h; >> + } else { >> new_transport = transport_h2g; >> + } >> break; > > The old code had `!transport_h2g` in the second else-if condition at line > -583, which routed all CID > VMADDR_CID_HOST traffic to transport_g2h when > no H2G transport was loaded. The new code removes this check. > > When transport_h2g is NULL (no H2G transport loaded) and the G2H transport > does not implement has_remote_cid (as is the case for VMCI and Hyper-V > transports), what happens? > > The G2H fallback branch at line +596 requires > `transport_g2h->has_remote_cid` to be non-NULL. If it's NULL, the > short-circuit evaluation skips this branch and executes the final else at > line +601, setting `new_transport = transport_h2g` (which is NULL), > ultimately returning -ENODEV. > > The commit message explicitly states the intent to preserve the existing > no-H2G fallback behavior. Does this implementation break it for G2H > transports that do not implement the new optional has_remote_cid callback? > > This affects VMCI and Hyper-V environments: when no H2G transport is > loaded, CID > 2 connections that previously fell back to G2H now get > ENODEV. Other comments from AI looked like nit picking to me, but the above one looks relevant. I forwarded verbatim all the feedback for completeness.
/P
