Thanks Greg, Stefano, tldr; withdrawing the regression -- rust-vmm vsock mistake -- We're not strictly tied to the 6.1.x tree but generally stick with the long term releases because we patch every week or so and want less to change if possible. I think you're exactly right re: rust-vmm's vsock. We're using cloud hypervisor and just tried updating to a fixed version and everything is working as expected. https://github.com/rust-vmm/vm-virtio/issues/204 (thanks Stefano) Thanks all... nothing to see. - Simon On Mon, Dec 11, 2023 at 3:39 AM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote: > > On Mon, Dec 11, 2023 at 5:05 AM Simon Kaegi <simon.kaegi@xxxxxxxxx> wrote: > > > > #regzbot introduced v6.1.62..v6.1.63 > > #regzbot introduced: baddcc2c71572968cdaeee1c4ab3dc0ad90fa765 > > > > We hit this regression when updating our guest vm kernel from 6.1.62 to > > 6.1.63 -- bisecting, this problem was introduced > > in baddcc2c71572968cdaeee1c4ab3dc0ad90fa765 -- virtio/vsock: replace > > virtio_vsock_pkt with sk_buff -- > > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.1.63&id=baddcc2c71572968cdaeee1c4ab3dc0ad90fa765 > > > > We're getting a timeout when trying to connect to the vsocket in the > > guest VM when launching a kata containers 3.2.0 agent. We haven't done > > much more to understand the problem at this point. > > It looks like the same issue described here: > https://github.com/rust-vmm/vm-virtio/issues/204 > > In summary that patch also contains a performance improvement, because > by switching to sk_buffs, we can use only one descriptor for the whole > packet (header + payload), whereas before we used two for each packet. > Some devices (e.g. rust-vmm's vsock) mistakenly always expect 2 > descriptors, but this is a violation of the VIRTIO specification. > > Which device are you using? > > Can you confirm that your device conforms to the specification? > > Stefano > > > > > We can reproduce 100% of the time but don't currently have a simple > > reproducer as the problem was found in our build service which uses > > kata-containers (with cloud-hypervisor). > > > > We have not checked the mainline as we currently are tied to 6.1.x. > > > > -Simon > > >
