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 >
