Assertion failed: (!REPLY_RING_EMPTY(sc)), function send_response_common, file src/lib/pci_virtio_sock.c, line 934.

In https://github.com/docker/for-mac/issues/2872#issuecomment-386560236 a Docker container is shutdown and a set of AF_VSOCK connections are simultaneously closed:

2018-05-02 15:21:58.519471-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.37/containers/ce3d053af106a4f13790f82e721f88ece
8e85aa907f465afbc59d7f78cbc3676/wait?condition=next-exit
2018-05-02 15:21:58.520536-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.37/containers/ce3d053af106a4f13790f82e721f88ece8e85aa907f465afbc59d7f78cbc3676/attach?stderr=1&stdin=1&stdout=1&stream=1
2018-05-02 15:21:58.559605-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/777ba957b4f05c6b359a64c4dfe54383e8d3e3e0374c23d82dfd69284fd1333b/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.560708-0700  localhost com.docker.driver.amd64-linux[19791]: Error forwarding raw stream from container: write unix s60->: write: broken pipe
2018-05-02 15:21:58.560819-0700  localhost com.docker.driver.amd64-linux[19791]: Error closing raw stream from container: close unix s60->: shutdown: socket is not connected
2018-05-02 15:21:58.560880-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/7374b83bcea635423f15aaaebe0e68c52de4f783393f3f03c5d4c04bfe792f58/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.560971-0700  localhost com.docker.driver.amd64-linux[19791]: Error forwarding raw stream from container: write unix s60->: write: broken pipe
2018-05-02 15:21:58.561036-0700  localhost com.docker.driver.amd64-linux[19791]: Error closing raw stream from container: close unix s60->: shutdown: socket is not connected
2018-05-02 15:21:58.561133-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/6b12ec8ec282ed688811f66dd5dfc06fb1baa8ab0de37ead0bb4aa401dc285c6/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.561180-0700  localhost com.docker.driver.amd64-linux[19791]: Error forwarding raw stream from container: write unix s60->: write: broken pipe
2018-05-02 15:21:58.561217-0700  localhost com.docker.driver.amd64-linux[19791]: Error closing raw stream from container: close unix s60->: shutdown: socket is not connected
2018-05-02 15:21:58.561276-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/1d3c0a5d337ac23ff97ae6b561cf40bde538181e348800e89f7dc4fa3edc6877/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.561370-0700  localhost com.docker.driver.amd64-linux[19791]: Error forwarding raw stream from container: write unix s60->: write: broken pipe
2018-05-02 15:21:58.561438-0700  localhost com.docker.driver.amd64-linux[19791]: Error closing raw stream from container: close unix s60->: shutdown: socket is not connected
2018-05-02 15:21:58.561588-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/764caeb2552f7eeda49f6292fc104e0173fa8952376f17c99395d86d59aa1ef5/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.561650-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/989e12d766b90e09fb66cf34c2761737eb8dee757530dcd8eccb78d890f8443e/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.561720-0700  localhost com.docker.driver.amd64-linux[19791]: Error forwarding raw stream from container: write unix s60->: write: broken pipe
2018-05-02 15:21:58.561750-0700  localhost com.docker.driver.amd64-linux[19791]: Error closing raw stream from container: close unix s60->: shutdown: socket is not connected
2018-05-02 15:21:58.561910-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/7367d897b4239a174ef2d7bc5df9e3a58cfddbb7780de092ae779286515a35d6/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.561919-0700  localhost com.docker.driver.amd64-linux[19791]: Error forwarding raw stream from container: write unix s60->: write: broken pipe
2018-05-02 15:21:58.561974-0700  localhost com.docker.driver.amd64-linux[19791]: Error closing raw stream from container: close unix s60->: shutdown: socket is not connected
2018-05-02 15:21:58.562102-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/b7c958118e20cd6aebbe20081dd0bdbec34f6b1844bb10e607635d64caf8c935/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.562167-0700  localhost com.docker.driver.amd64-linux[19791]: Error forwarding raw stream from container: write unix s60->: write: broken pipe
2018-05-02 15:21:58.562189-0700  localhost com.docker.driver.amd64-linux[19791]: Error closing raw stream from container: close unix s60->: shutdown: socket is not connected
2018-05-02 15:21:58.562222-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/b43381a52e98a6f057e3eb3ddb22b11d7ba7df43ad0a3eaac30b2358da8e7fb5/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.562407-0700  localhost com.docker.driver.amd64-linux[19791]: Error forwarding raw stream from container: write unix s60->: write: broken pipe
2018-05-02 15:21:58.562431-0700  localhost com.docker.driver.amd64-linux[19791]: Error closing raw stream from container: close unix s60->: shutdown: socket is not connected
2018-05-02 15:21:58.562466-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/2734b5133d06521b91cbf12ec933d4e6710388dc58ca8224f91256c2b26b3066/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.565070-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/0ebb0d164dcb574a1c9293f4b89f6c5980b28ea6b7afbbfa02f61c48aafc5d62/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.565306-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/1a10c59d4fd2ff59249fd950bac9c6e98cda4bd2e63e8418cbd9121c95e1e649/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.565350-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/23febad602e8110ae73f53887e8c5c8547cbcc41c788705216426403a4cf57f8/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.565941-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/25549937a3743c5771ef8c7354be68090ad1e057302f723ed7a1decd3fe25391/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.566170-0700  localhost com.docker.driver.amd64-linux[19791]: Error forwarding raw stream from container: write unix s60->: write: broken pipe
2018-05-02 15:21:58.566198-0700  localhost com.docker.driver.amd64-linux[19791]: Error closing raw stream from container: close unix s60->: shutdown: socket is not connected
2018-05-02 15:21:58.566319-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/f4288843126045dc510da935b41319d9c261ed9b4c2636885d0b240c5224204e/attach?logs=0&stdout=1&stderr=1&stream=1
2018-05-02 15:21:58.566712-0700  localhost com.docker.driver.amd64-linux[19791]: proxy << POST /v1.25/containers/0d618ab342e4225c4ddd8aeebc45dd1497d9775aa2a30b35ed9588e7af30ddfd/attach?logs=0&stdout=1&stderr=1&stream=1

This triggers

2018-05-02 15:22:03.400455-0700  localhost com.docker.driver.amd64-linux[19791]: Assertion failed: (!REPLY_RING_EMPTY(sc)), function send_response_common, file src/lib/pci_virtio_sock.c, line 934.

the code has:

        /*
         * We have just incremented reply_prod above but we hold the
         * lock so the consumer cannot have caught us up. Hence for
         * the ring to appear empty it must actually have just overflowed.
         */
        assert(!REPLY_RING_EMPTY(sc));

Start at src/lib/pci_virtio_sock.c around send_response_common line 934 and trace reply-ring handling during simultaneous AF_VSOCK connection closes. Reproduce the container shutdown sequence described in the report, then verify that the assertion no longer occurs during concurrent connection teardown.