From: Bobby Eshleman <bobbyeshleman@meta.com>

Add tests that validate vsock sockets are resilient to deleting
namespaces or changing namespace modes from global to local. The vsock
sockets should still function normally.

The function check_ns_changes_dont_break_connection() is added to re-use
the step-by-step logic of 1) setup connections, 2) do something that
would maybe break the connections, 3) check that the connections are
still ok.

Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
Changes in v9:
- more consistent shell style
- clarify -u usage comment for pipefile
---
 tools/testing/selftests/vsock/vmtest.sh | 123 ++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)

diff --git a/tools/testing/selftests/vsock/vmtest.sh b/tools/testing/selftests/vsock/vmtest.sh
index 9c12c1bd1edc..2b6e94aafc19 100755
--- a/tools/testing/selftests/vsock/vmtest.sh
+++ b/tools/testing/selftests/vsock/vmtest.sh
@@ -66,6 +66,12 @@ readonly TEST_NAMES=(
 	ns_same_local_loopback_ok
 	ns_same_local_host_connect_to_local_vm_ok
 	ns_same_local_vm_connect_to_local_host_ok
+	ns_mode_change_connection_continue_vm_ok
+	ns_mode_change_connection_continue_host_ok
+	ns_mode_change_connection_continue_both_ok
+	ns_delete_vm_ok
+	ns_delete_host_ok
+	ns_delete_both_ok
 )
 readonly TEST_DESCS=(
 	# vm_server_host_client
@@ -135,6 +141,24 @@ readonly TEST_DESCS=(
 
 	# ns_same_local_vm_connect_to_local_host_ok
 	"Run vsock_test client in VM in a local ns with server in same ns."
+
+	# ns_mode_change_connection_continue_vm_ok
+	"Check that changing NS mode of VM namespace from global to local after a connection is established doesn't break the connection"
+
+	# ns_mode_change_connection_continue_host_ok
+	"Check that changing NS mode of host namespace from global to local after a connection is established doesn't break the connection"
+
+	# ns_mode_change_connection_continue_both_ok
+	"Check that changing NS mode of host and VM namespaces from global to local after a connection is established doesn't break the connection"
+
+	# ns_delete_vm_ok
+	"Check that deleting the VM's namespace does not break the socket connection"
+
+	# ns_delete_host_ok
+	"Check that deleting the host's namespace does not break the socket connection"
+
+	# ns_delete_both_ok
+	"Check that deleting the VM and host's namespaces does not break the socket connection"
 )
 
 readonly USE_SHARED_VM=(
@@ -1256,6 +1280,105 @@ test_ns_vm_local_mode_rejected() {
 	return "${KSFT_PASS}"
 }
 
+check_ns_changes_dont_break_connection() {
+	local pipefile pidfile outfile
+	local ns0="global0"
+	local ns1="global1"
+	local port=12345
+	local pids=()
+	local rc=0
+
+	init_namespaces
+
+	pidfile="$(create_pidfile)"
+	if ! vm_start "${pidfile}" "${ns0}"; then
+		return "${KSFT_FAIL}"
+	fi
+	vm_wait_for_ssh "${ns0}"
+
+	outfile=$(mktemp)
+	vm_ssh "${ns0}" -- \
+		socat VSOCK-LISTEN:"${port}",fork STDOUT > "${outfile}" 2>/dev/null &
+	pids+=($!)
+
+	# wait_for_listener() does not work for vsock because vsock does not
+	# export socket state to /proc/net/. Instead, we have no choice but to
+	# sleep for some hardcoded time.
+	sleep "${WAIT_PERIOD}"
+
+	# We use a pipe here so that we can echo into the pipe instead of using
+	# socat and a unix socket file. We just need a name for the pipe (not a
+	# regular file) so use -u.
+	pipefile=$(mktemp -u /tmp/vmtest_pipe_XXXX)
+	ip netns exec "${ns1}" \
+		socat PIPE:"${pipefile}" VSOCK-CONNECT:"${VSOCK_CID}":"${port}" &
+	pids+=($!)
+
+	timeout "${WAIT_PERIOD}" \
+		bash -c 'while [[ ! -e '"${pipefile}"' ]]; do sleep 1; done; exit 0'
+
+	if [[ $2 == "delete" ]]; then
+		if [[ "$1" == "vm" ]]; then
+			ip netns del "${ns0}"
+		elif [[ "$1" == "host" ]]; then
+			ip netns del "${ns1}"
+		elif [[ "$1" == "both" ]]; then
+			ip netns del "${ns0}"
+			ip netns del "${ns1}"
+		fi
+	elif [[ $2 == "change_mode" ]]; then
+		if [[ "$1" == "vm" ]]; then
+			ns_set_mode "${ns0}" "local"
+		elif [[ "$1" == "host" ]]; then
+			ns_set_mode "${ns1}" "local"
+		elif [[ "$1" == "both" ]]; then
+			ns_set_mode "${ns0}" "local"
+			ns_set_mode "${ns1}" "local"
+		fi
+	fi
+
+	echo "TEST" > "${pipefile}"
+
+	timeout "${WAIT_PERIOD}" \
+		bash -c 'while [[ ! -s '"${outfile}"' ]]; do sleep 1; done; exit 0'
+
+	if grep -q "TEST" "${outfile}"; then
+		rc="${KSFT_PASS}"
+	else
+		rc="${KSFT_FAIL}"
+	fi
+
+	terminate_pidfiles "${pidfile}"
+	terminate_pids "${pids[@]}"
+	rm -f "${outfile}"
+
+	return "${rc}"
+}
+
+test_ns_mode_change_connection_continue_vm_ok() {
+	check_ns_changes_dont_break_connection "vm" "change_mode"
+}
+
+test_ns_mode_change_connection_continue_host_ok() {
+	check_ns_changes_dont_break_connection "host" "change_mode"
+}
+
+test_ns_mode_change_connection_continue_both_ok() {
+	check_ns_changes_dont_break_connection "both" "change_mode"
+}
+
+test_ns_delete_vm_ok() {
+	check_ns_changes_dont_break_connection "vm" "delete"
+}
+
+test_ns_delete_host_ok() {
+	check_ns_changes_dont_break_connection "host" "delete"
+}
+
+test_ns_delete_both_ok() {
+	check_ns_changes_dont_break_connection "both" "delete"
+}
+
 shared_vm_test() {
 	local tname
 

-- 
2.47.3

On Mon, Nov 17, 2025 at 06:00:34PM -0800, Bobby Eshleman wrote:
>From: Bobby Eshleman <bobbyeshleman@meta.com>
>
>Add tests that validate vsock sockets are resilient to deleting
>namespaces or changing namespace modes from global to local. The vsock
>sockets should still function normally.
>
>The function check_ns_changes_dont_break_connection() is added to re-use
>the step-by-step logic of 1) setup connections, 2) do something that
>would maybe break the connections, 3) check that the connections are
>still ok.
>
>Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
>---
>Changes in v9:
>- more consistent shell style
>- clarify -u usage comment for pipefile
>---
> tools/testing/selftests/vsock/vmtest.sh | 123 ++++++++++++++++++++++++++++++++
> 1 file changed, 123 insertions(+)
>
>diff --git a/tools/testing/selftests/vsock/vmtest.sh b/tools/testing/selftests/vsock/vmtest.sh
>index 9c12c1bd1edc..2b6e94aafc19 100755
>--- a/tools/testing/selftests/vsock/vmtest.sh
>+++ b/tools/testing/selftests/vsock/vmtest.sh
>@@ -66,6 +66,12 @@ readonly TEST_NAMES=(
> 	ns_same_local_loopback_ok
> 	ns_same_local_host_connect_to_local_vm_ok
> 	ns_same_local_vm_connect_to_local_host_ok
>+	ns_mode_change_connection_continue_vm_ok
>+	ns_mode_change_connection_continue_host_ok
>+	ns_mode_change_connection_continue_both_ok
>+	ns_delete_vm_ok
>+	ns_delete_host_ok
>+	ns_delete_both_ok
> )
> readonly TEST_DESCS=(
> 	# vm_server_host_client
>@@ -135,6 +141,24 @@ readonly TEST_DESCS=(
>
> 	# ns_same_local_vm_connect_to_local_host_ok
> 	"Run vsock_test client in VM in a local ns with server in same ns."
>+
>+	# ns_mode_change_connection_continue_vm_ok
>+	"Check that changing NS mode of VM namespace from global to local after a connection is established doesn't break the connection"
>+
>+	# ns_mode_change_connection_continue_host_ok
>+	"Check that changing NS mode of host namespace from global to 
>local after a connection is established doesn't break the connection"
>+
>+	# ns_mode_change_connection_continue_both_ok
>+	"Check that changing NS mode of host and VM namespaces from global to local after a connection is established doesn't break the connection"
>+
>+	# ns_delete_vm_ok
>+	"Check that deleting the VM's namespace does not break the socket connection"
>+
>+	# ns_delete_host_ok
>+	"Check that deleting the host's namespace does not break the socket connection"
>+
>+	# ns_delete_both_ok
>+	"Check that deleting the VM and host's namespaces does not break the socket connection"
> )
>
> readonly USE_SHARED_VM=(
>@@ -1256,6 +1280,105 @@ test_ns_vm_local_mode_rejected() {
> 	return "${KSFT_PASS}"
> }
>
>+check_ns_changes_dont_break_connection() {
>+	local pipefile pidfile outfile
>+	local ns0="global0"
>+	local ns1="global1"
>+	local port=12345
>+	local pids=()
>+	local rc=0
>+
>+	init_namespaces
>+
>+	pidfile="$(create_pidfile)"
>+	if ! vm_start "${pidfile}" "${ns0}"; then
>+		return "${KSFT_FAIL}"
>+	fi
>+	vm_wait_for_ssh "${ns0}"
>+
>+	outfile=$(mktemp)
>+	vm_ssh "${ns0}" -- \
>+		socat VSOCK-LISTEN:"${port}",fork STDOUT > "${outfile}" 2>/dev/null &
>+	pids+=($!)
>+
>+	# wait_for_listener() does not work for vsock because vsock does not
>+	# export socket state to /proc/net/. Instead, we have no choice but to
>+	# sleep for some hardcoded time.
>+	sleep "${WAIT_PERIOD}"

can we use `ss --vsock --listening` ?

>+
>+	# We use a pipe here so that we can echo into the pipe instead of using
>+	# socat and a unix socket file. We just need a name for the pipe (not a
>+	# regular file) so use -u.
>+	pipefile=$(mktemp -u /tmp/vmtest_pipe_XXXX)

Should we remove this file at the end of the test?

>+	ip netns exec "${ns1}" \
>+		socat PIPE:"${pipefile}" VSOCK-CONNECT:"${VSOCK_CID}":"${port}" &
>+	pids+=($!)
>+
>+	timeout "${WAIT_PERIOD}" \
>+		bash -c 'while [[ ! -e '"${pipefile}"' ]]; do sleep 1; done; exit 0'
>+
>+	if [[ $2 == "delete" ]]; then
>+		if [[ "$1" == "vm" ]]; then
>+			ip netns del "${ns0}"
>+		elif [[ "$1" == "host" ]]; then
>+			ip netns del "${ns1}"
>+		elif [[ "$1" == "both" ]]; then
>+			ip netns del "${ns0}"
>+			ip netns del "${ns1}"
>+		fi
>+	elif [[ $2 == "change_mode" ]]; then
>+		if [[ "$1" == "vm" ]]; then
>+			ns_set_mode "${ns0}" "local"
>+		elif [[ "$1" == "host" ]]; then
>+			ns_set_mode "${ns1}" "local"
>+		elif [[ "$1" == "both" ]]; then
>+			ns_set_mode "${ns0}" "local"
>+			ns_set_mode "${ns1}" "local"
>+		fi
>+	fi
>+
>+	echo "TEST" > "${pipefile}"
>+
>+	timeout "${WAIT_PERIOD}" \
>+		bash -c 'while [[ ! -s '"${outfile}"' ]]; do sleep 1; done; exit 0'
>+
>+	if grep -q "TEST" "${outfile}"; then
>+		rc="${KSFT_PASS}"
>+	else
>+		rc="${KSFT_FAIL}"
>+	fi
>+
>+	terminate_pidfiles "${pidfile}"
>+	terminate_pids "${pids[@]}"
>+	rm -f "${outfile}"
>+
>+	return "${rc}"
>+}
>+
>+test_ns_mode_change_connection_continue_vm_ok() {
>+	check_ns_changes_dont_break_connection "vm" "change_mode"
>+}
>+
>+test_ns_mode_change_connection_continue_host_ok() {
>+	check_ns_changes_dont_break_connection "host" "change_mode"
>+}
>+
>+test_ns_mode_change_connection_continue_both_ok() {
>+	check_ns_changes_dont_break_connection "both" "change_mode"
>+}
>+
>+test_ns_delete_vm_ok() {
>+	check_ns_changes_dont_break_connection "vm" "delete"
>+}
>+
>+test_ns_delete_host_ok() {
>+	check_ns_changes_dont_break_connection "host" "delete"
>+}
>+
>+test_ns_delete_both_ok() {
>+	check_ns_changes_dont_break_connection "both" "delete"
>+}
>+
> shared_vm_test() {
> 	local tname
>
>
>-- 
>2.47.3
>