On Wed, Jan 07, 2026 at 10:47:56AM +0100, Paolo Abeni wrote: > Hi, > > On 12/2/25 11:01 PM, Bobby Eshleman wrote: > > On Tue, Dec 02, 2025 at 09:47:19PM +0100, Paolo Abeni wrote: > >> I still have some concern WRT the dynamic mode change after netns > >> creation. I fear some 'unsolvable' (or very hard to solve) race I can't > >> see now. A tcp_child_ehash_entries-like model will avoid completely the > >> issue, but I understand it would be a significant change over the > >> current status. > >> > >> "Luckily" the merge window is on us and we have some time to discuss. Do > >> you have a specific use-case for the ability to change the netns mode > >> after creation? > >> > >> /P > > > > I don't think there is a hard requirement that the mode be change-able > > after creation. Though I'd love to avoid such a big change... or at > > least leave unchanged as much of what we've already reviewed as > > possible. > > > > In the scheme of defining the mode at creation and following the > > tcp_child_ehash_entries-ish model, what I'm imagining is: > > - /proc/sys/net/vsock/child_ns_mode can be set to "local" or "global" > > - /proc/sys/net/vsock/child_ns_mode is not immutable, can change any > > number of times > > > > - when a netns is created, the new netns mode is inherited from > > child_ns_mode, being assigned using something like: > > > > net->vsock.ns_mode = > > get_net_ns_by_pid(current->pid)->child_ns_mode > > > > - /proc/sys/net/vsock/ns_mode queries the current mode, returning > > "local" or "global", returning value of net->vsock.ns_mode > > - /proc/sys/net/vsock/ns_mode and net->vsock.ns_mode are immutable and > > reject writes > > > > Does that align with what you have in mind? > Sorry for the latency. This fell of my radar while I still processed PW > before EoY and afterwards I had some break. > > Yes, the above aligns with what I suggested, and I think it should solve > possible race-related concerns (but I haven't looked at the RFC). > > /P > >
No worries, understandable! Thanks for the confirmation. Best, Bobby
