Re: [PATCH net-next v12 11/12] selftests/vsock: add tests for host <-> vm connectivity with namespaces

On Wed, Nov 26, 2025 at 11:47:40PM -0800, Bobby Eshleman wrote:

From: Bobby Eshleman bobbyeshleman@meta.com

Add tests to validate namespace correctness using vsock_test and socat. The vsock_test tool is used to validate expected success tests, but socat is used for expected failure tests. socat is used to ensure that connections are rejected outright instead of failing due to some other socket behavior (as tested in vsock_test). Additionally, socat is already required for tunneling TCP traffic from vsock_test. Using only one of the vsock_test tests like 'test_stream_client_close_client' would have yielded a similar result, but doing so wouldn't remove the socat dependency.

Additionally, check for the dependency socat. socat needs special handling beyond just checking if it is on the path because it must be compiled with support for both vsock and unix. The function check_socat() checks that this support exists.

Add more padding to test name printf strings because the tests added in this patch would otherwise overflow.

Add vm_dmesg_* helpers to encapsulate checking dmesg for oops and warnings.

Add ability to pass extra args to host-side vsock_test so that tests that cause false positives may be skipped with arg --skip.

Signed-off-by: Bobby Eshleman bobbyeshleman@meta.com

Changes in v12:

• add test skip (vsock_test test 29) when host_vsock_test() uses client

mode in a local namespace. Test 29 causes a false positive to trigger.

I see, LGTM and thanks for adding a comment with the reason!

Reviewed-by: Stefano Garzarella sgarzare@redhat.com

Changes in v11:

• add 'sleep "${WAIT_PERIOD}"' after any non-TCP socat LISTEN cmd

(Stefano)

• add host_wait_for_listener() after any socat TCP-LISTEN (Stefano)
• reuse vm_dmesg_{oops,warn}_count() inside vm_dmesg_check()
• fix copy-paste in test_ns_same_local_vm_connect_to_local_host_ok()

(Stefano)

Changes in v10:

• add vm_dmesg_start() and vm_dmesg_check()

Changes in v9:

• consistent variable quoting

---

tools/testing/selftests/vsock/vmtest.sh | 572 +++++++++++++++++++++++++++++++- 1 file changed, 568 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/vsock/vmtest.sh b/tools/testing/selftests/vsock/vmtest.sh index ec18eb5b4ccd..da9198dc8ab5 100755 --- a/tools/testing/selftests/vsock/vmtest.sh +++ b/tools/testing/selftests/vsock/vmtest.sh @@ -7,6 +7,7 @@ # * virtme-ng # * busybox-static (used by virtme-ng) # * qemu (used by virtme-ng) +# * socat # # shellcheck disable=SC2317,SC2119

@@ -54,6 +55,19 @@ readonly TEST_NAMES=( ns_local_same_cid_ok ns_global_local_same_cid_ok ns_local_global_same_cid_ok

• ns_diff_global_host_connect_to_global_vm_ok
• ns_diff_global_host_connect_to_local_vm_fails
• ns_diff_global_vm_connect_to_global_host_ok
• ns_diff_global_vm_connect_to_local_host_fails
• ns_diff_local_host_connect_to_local_vm_fails
• ns_diff_local_vm_connect_to_local_host_fails
• ns_diff_global_to_local_loopback_local_fails
• ns_diff_local_to_global_loopback_fails
• ns_diff_local_to_local_loopback_fails
• ns_diff_global_to_global_loopback_ok
• ns_same_local_loopback_ok
• ns_same_local_host_connect_to_local_vm_ok
• ns_same_local_vm_connect_to_local_host_ok

) readonly TEST_DESCS=( # vm_server_host_client @@ -82,6 +96,45 @@ readonly TEST_DESCS=(

# ns_local_global_same_cid_ok "Check QEMU successfully starts one VM in a local ns and then another VM in a global ns with the same CID."

• # ns_diff_global_host_connect_to_global_vm_ok
• "Run vsock_test client in global ns with server in VM in another global ns."
• # ns_diff_global_host_connect_to_local_vm_fails
• "Run socat to test a process in a global ns fails to connect to a VM in a local ns."
• # ns_diff_global_vm_connect_to_global_host_ok
• "Run vsock_test client in VM in a global ns with server in another global ns."
• # ns_diff_global_vm_connect_to_local_host_fails
• "Run socat to test a VM in a global ns fails to connect to a host process in a local ns."
• # ns_diff_local_host_connect_to_local_vm_fails
• "Run socat to test a host process in a local ns fails to connect to a VM in another local ns."
• # ns_diff_local_vm_connect_to_local_host_fails
• "Run socat to test a VM in a local ns fails to connect to a host process in another local ns."
• # ns_diff_global_to_local_loopback_local_fails
• "Run socat to test a loopback vsock in a global ns fails to connect to a vsock in a local ns."
• # ns_diff_local_to_global_loopback_fails
• "Run socat to test a loopback vsock in a local ns fails to connect to a vsock in a global ns."
• # ns_diff_local_to_local_loopback_fails
• "Run socat to test a loopback vsock in a local ns fails to connect to a vsock in another local ns."
• # ns_diff_global_to_global_loopback_ok
• "Run socat to test a loopback vsock in a global ns successfully connects to a vsock in another global ns."
• # ns_same_local_loopback_ok
• "Run socat to test a loopback vsock in a local ns successfully connects to a vsock in the same ns."
• # ns_same_local_host_connect_to_local_vm_ok
• "Run vsock_test client in a local ns with server in VM in same ns."
• # ns_same_local_vm_connect_to_local_host_ok
• "Run vsock_test client in VM in a local ns with server in same ns."

)

readonly USE_SHARED_VM=( @@ -112,7 +165,7 @@ usage() { for ((i = 0; i < ${#TEST_NAMES[@]}; i++)); do name=${TEST_NAMES[${i}]} desc=${TEST_DESCS[${i}]}

• printf "\t%-35s%-35s\n" "${name}" "${desc}"
  

• printf "\t%-55s%-35s\n" "${name}" "${desc}"
  

  done echo

@@ -231,7 +284,7 @@ check_args() { }

check_deps() {

• for dep in vng ${QEMU} busybox pkill ssh ss; do

• for dep in vng ${QEMU} busybox pkill ssh ss socat; do if [[ ! -x $(command -v "${dep}") ]]; then echo -e "skip: dependency ${dep} not found!\n" exit "${KSFT_SKIP}"

@@ -282,6 +335,20 @@ check_vng() { fi }

+check_socat() {

• local support_string
• support_string="$(socat -V)"
• if [[ "${support_string}" != *"WITH_VSOCK 1"* ]]; then

• die "err: socat is missing vsock support"
  

• fi
• if [[ "${support_string}" != *"WITH_UNIX 1"* ]]; then

• die "err: socat is missing unix support"
  

• fi

+}

handle_build() { if [[ ! "${BUILD}" -eq 1 ]]; then return @@ -330,6 +397,14 @@ terminate_pidfiles() { done }

+terminate_pids() {

• local pid
• for pid in "$@"; do

• kill -SIGTERM "${pid}" &>/dev/null || :
  

• done

+}

vm_start() { local pidfile=$1 local ns=$2 @@ -468,6 +543,28 @@ vm_dmesg_warn_count() { vm_ssh "${ns}" -- dmesg --level=warn 2>/dev/null | grep -c -i 'vsock' }

+vm_dmesg_check() {

• local pidfile=$1
• local ns=$2
• local oops_before=$3
• local warn_before=$4
• local oops_after warn_after
• oops_after=$(vm_dmesg_oops_count "${ns}")
• if [[ "${oops_after}" -gt "${oops_before}" ]]; then

• echo "FAIL: kernel oops detected on vm in ns ${ns}" | log_host
  

• return 1
  

• fi
• warn_after=$(vm_dmesg_warn_count "${ns}")
• if [[ "${warn_after}" -gt "${warn_before}" ]]; then

• echo "FAIL: kernel warning detected on vm in ns ${ns}" | log_host
  

• return 1
  

• fi
• return 0

+}

vm_vsock_test() { local ns=$1 local host=$2 @@ -511,6 +608,8 @@ host_vsock_test() { local host=$2 local cid=$3 local port=$4

• shift 4

• local extra_args=("$@") local rc

  local cmd="${VSOCK_TEST}"

@@ -525,13 +624,15 @@ host_vsock_test() { --mode=client \ --peer-cid="${cid}" \ --control-host="${host}" \

• 	--control-port="${port}" 2>&1 | log_host
  

• 	--control-port="${port}" \
  

• 	"${extra_args[@]}" 2>&1 | log_host
  

  rc=$? else ${cmd} \ --mode=server \ --peer-cid="${cid}" \

• 	--control-port="${port}" 2>&1 | log_host &
  

• 	--control-port="${port}" \
  

• 	"${extra_args[@]}" 2>&1 | log_host &
  

  rc=$?

  if [[ $rc -ne 0 ]]; then

@@ -592,6 +693,468 @@ test_ns_host_vsock_ns_mode_ok() { return "${KSFT_PASS}" }

+test_ns_diff_global_host_connect_to_global_vm_ok() {

• local oops_before warn_before
• local pids pid pidfile
• local ns0 ns1 port
• declare -a pids
• local unixfile
• ns0="global0"
• ns1="global1"
• port=1234
• local rc
• init_namespaces
• pidfile="$(create_pidfile)"
• if ! vm_start "${pidfile}" "${ns0}"; then

• return "${KSFT_FAIL}"
  

• fi
• vm_wait_for_ssh "${ns0}"
• oops_before=$(vm_dmesg_oops_count "${ns0}")
• warn_before=$(vm_dmesg_warn_count "${ns0}")
• unixfile=$(mktemp -u /tmp/XXXX.sock)
• ip netns exec "${ns1}" \

• socat TCP-LISTEN:"${TEST_HOST_PORT}",fork \
  

• 	UNIX-CONNECT:"${unixfile}" &
  

• pids+=($!)
• host_wait_for_listener "${ns1}" "${TEST_HOST_PORT}" "tcp"
• ip netns exec "${ns0}" socat UNIX-LISTEN:"${unixfile}",fork \

• TCP-CONNECT:localhost:"${TEST_HOST_PORT}" &
  

• pids+=($!)
• host_wait_for_listener "${ns0}" "${unixfile}" "unix"
• vm_vsock_test "${ns0}" "server" 2 "${TEST_GUEST_PORT}"
• vm_wait_for_listener "${ns0}" "${TEST_GUEST_PORT}" "tcp"
• host_vsock_test "${ns1}" "127.0.0.1" "${VSOCK_CID}" "${TEST_HOST_PORT}"
• rc=$?
• vm_dmesg_check "${pidfile}" "${ns0}" "${oops_before}" "${warn_before}"
• dmesg_rc=$?
• terminate_pids "${pids[@]}"
• terminate_pidfiles "${pidfile}"
• if [[ "${rc}" -ne 0 ]] || [[ "${dmesg_rc}" -ne 0 ]]; then

• return "${KSFT_FAIL}"
  

• fi
• return "${KSFT_PASS}"

+}

+test_ns_diff_global_host_connect_to_local_vm_fails() {

• local oops_before warn_before
• local ns0="global0"
• local ns1="local0"
• local port=12345
• local dmesg_rc
• local pidfile
• local result
• local pid
• init_namespaces
• outfile=$(mktemp)
• pidfile="$(create_pidfile)"
• if ! vm_start "${pidfile}" "${ns1}"; then

• log_host "failed to start vm (cid=${VSOCK_CID}, ns=${ns0})"
  

• return "${KSFT_FAIL}"
  

• fi
• vm_wait_for_ssh "${ns1}"
• oops_before=$(vm_dmesg_oops_count "${ns1}")
• warn_before=$(vm_dmesg_warn_count "${ns1}")
• vm_ssh "${ns1}" -- socat VSOCK-LISTEN:"${port}" STDOUT > "${outfile}" &
• vm_wait_for_listener "${ns1}" "${port}" "vsock"
• echo TEST | ip netns exec "${ns0}" \

• socat STDIN VSOCK-CONNECT:"${VSOCK_CID}":"${port}" 2>/dev/null
  

• vm_dmesg_check "${pidfile}" "${ns1}" "${oops_before}" "${warn_before}"
• dmesg_rc=$?
• terminate_pidfiles "${pidfile}"
• result=$(cat "${outfile}")
• rm -f "${outfile}"
• if [[ "${result}" == "TEST" ]] || [[ "${dmesg_rc}" -ne 0 ]]; then

• return "${KSFT_FAIL}"
  

• fi
• return "${KSFT_PASS}"

+}

+test_ns_diff_global_vm_connect_to_global_host_ok() {

• local oops_before warn_before
• local ns0="global0"
• local ns1="global1"
• local port=12345
• local unixfile
• local dmesg_rc
• local pidfile
• local pids
• local rc
• init_namespaces
• declare -a pids
• log_host "Setup socat bridge from ns ${ns0} to ns ${ns1} over port ${port}"
• unixfile=$(mktemp -u /tmp/XXXX.sock)
• ip netns exec "${ns0}" \

• socat TCP-LISTEN:"${port}" UNIX-CONNECT:"${unixfile}" &
  

• pids+=($!)
• host_wait_for_listener "${ns0}" "${port}" "tcp"
• ip netns exec "${ns1}" \

• socat UNIX-LISTEN:"${unixfile}" TCP-CONNECT:127.0.0.1:"${port}" &
  

• pids+=($!)
• host_wait_for_listener "${ns1}" "${unixfile}" "unix"
• log_host "Launching ${VSOCK_TEST} in ns ${ns1}"
• host_vsock_test "${ns1}" "server" "${VSOCK_CID}" "${port}"
• pidfile="$(create_pidfile)"
• if ! vm_start "${pidfile}" "${ns0}"; then

• log_host "failed to start vm (cid=${cid}, ns=${ns0})"
  

• terminate_pids "${pids[@]}"
  

• rm -f "${unixfile}"
  

• return "${KSFT_FAIL}"
  

• fi
• vm_wait_for_ssh "${ns0}"
• oops_before=$(vm_dmesg_oops_count "${ns0}")
• warn_before=$(vm_dmesg_warn_count "${ns0}")
• vm_vsock_test "${ns0}" "10.0.2.2" 2 "${port}"
• rc=$?
• vm_dmesg_check "${pidfile}" "${ns0}" "${oops_before}" "${warn_before}"
• dmesg_rc=$?
• terminate_pidfiles "${pidfile}"
• terminate_pids "${pids[@]}"
• rm -f "${unixfile}"
• if [[ "${rc}" -ne 0 ]] || [[ "${dmesg_rc}" -ne 0 ]]; then

• return "${KSFT_FAIL}"
  

• fi
• return "${KSFT_PASS}"

+}

+test_ns_diff_global_vm_connect_to_local_host_fails() {

• local ns0="global0"
• local ns1="local0"
• local port=12345
• local oops_before warn_before
• local dmesg_rc
• local pidfile
• local result
• local pid
• init_namespaces
• log_host "Launching socat in ns ${ns1}"
• outfile=$(mktemp)
• ip netns exec "${ns1}" socat VSOCK-LISTEN:"${port}" STDOUT &> "${outfile}" &
• pid=$!
• host_wait_for_listener "${ns1}" "${port}" "vsock"
• pidfile="$(create_pidfile)"
• if ! vm_start "${pidfile}" "${ns0}"; then

• log_host "failed to start vm (cid=${cid}, ns=${ns0})"
  

• terminate_pids "${pid}"
  

• rm -f "${outfile}"
  

• return "${KSFT_FAIL}"
  

• fi
• vm_wait_for_ssh "${ns0}"
• oops_before=$(vm_dmesg_oops_count "${ns0}")
• warn_before=$(vm_dmesg_warn_count "${ns0}")
• vm_ssh "${ns0}" -- \

• bash -c "echo TEST | socat STDIN VSOCK-CONNECT:2:${port}" 2>&1 | log_guest
  

• vm_dmesg_check "${pidfile}" "${ns0}" "${oops_before}" "${warn_before}"
• dmesg_rc=$?
• terminate_pidfiles "${pidfile}"
• terminate_pids "${pid}"
• result=$(cat "${outfile}")
• rm -f "${outfile}"
• if [[ "${result}" != TEST ]] && [[ "${dmesg_rc}" -eq 0 ]]; then

• return "${KSFT_PASS}"
  

• fi
• return "${KSFT_FAIL}"

+}

+test_ns_diff_local_host_connect_to_local_vm_fails() {

• local ns0="local0"
• local ns1="local1"
• local port=12345
• local oops_before warn_before
• local dmesg_rc
• local pidfile
• local result
• local pid
• init_namespaces
• outfile=$(mktemp)
• pidfile="$(create_pidfile)"
• if ! vm_start "${pidfile}" "${ns1}"; then

• log_host "failed to start vm (cid=${cid}, ns=${ns0})"
  

• return "${KSFT_FAIL}"
  

• fi
• vm_wait_for_ssh "${ns1}"
• oops_before=$(vm_dmesg_oops_count "${ns1}")
• warn_before=$(vm_dmesg_warn_count "${ns1}")
• vm_ssh "${ns1}" -- socat VSOCK-LISTEN:"${port}" STDOUT > "${outfile}" &
• vm_wait_for_listener "${ns1}" "${port}" "vsock"
• echo TEST | ip netns exec "${ns0}" \

• socat STDIN VSOCK-CONNECT:"${VSOCK_CID}":"${port}" 2>/dev/null
  

• vm_dmesg_check "${pidfile}" "${ns1}" "${oops_before}" "${warn_before}"
• dmesg_rc=$?
• terminate_pidfiles "${pidfile}"
• result=$(cat "${outfile}")
• rm -f "${outfile}"
• if [[ "${result}" != TEST ]] && [[ "${dmesg_rc}" -eq 0 ]]; then

• return "${KSFT_PASS}"
  

• fi
• return "${KSFT_FAIL}"

+}

+test_ns_diff_local_vm_connect_to_local_host_fails() {

• local oops_before warn_before
• local ns0="local0"
• local ns1="local1"
• local port=12345
• local dmesg_rc
• local pidfile
• local result
• local pid
• init_namespaces
• log_host "Launching socat in ns ${ns1}"
• outfile=$(mktemp)
• ip netns exec "${ns1}" socat VSOCK-LISTEN:"${port}" STDOUT &> "${outfile}" &
• pid=$!
• host_wait_for_listener "${ns1}" "${port}" "vsock"
• pidfile="$(create_pidfile)"
• if ! vm_start "${pidfile}" "${ns0}"; then

• log_host "failed to start vm (cid=${cid}, ns=${ns0})"
  

• rm -f "${outfile}"
  

• return "${KSFT_FAIL}"
  

• fi
• vm_wait_for_ssh "${ns0}"
• oops_before=$(vm_dmesg_oops_count "${ns0}")
• warn_before=$(vm_dmesg_warn_count "${ns0}")
• vm_ssh "${ns0}" -- \

• bash -c "echo TEST | socat STDIN VSOCK-CONNECT:2:${port}" 2>&1 | log_guest
  

• vm_dmesg_check "${pidfile}" "${ns0}" "${oops_before}" "${warn_before}"
• dmesg_rc=$?
• terminate_pidfiles "${pidfile}"
• terminate_pids "${pid}"
• result=$(cat "${outfile}")
• rm -f "${outfile}"
• if [[ "${result}" != TEST ]] && [[ "${dmesg_rc}" -eq 0 ]]; then

• return "${KSFT_PASS}"
  

• fi
• return "${KSFT_FAIL}"

+}

+__test_loopback_two_netns() {

• local ns0=$1
• local ns1=$2
• local port=12345
• local result
• local pid
• modprobe vsock_loopback &> /dev/null || :
• log_host "Launching socat in ns ${ns1}"
• outfile=$(mktemp)
• ip netns exec "${ns1}" socat VSOCK-LISTEN:"${port}" STDOUT > "${outfile}" 2>/dev/null &
• pid=$!
• host_wait_for_listener "${ns1}" "${port}" "vsock"
• log_host "Launching socat in ns ${ns0}"
• echo TEST | ip netns exec "${ns0}" socat STDIN VSOCK-CONNECT:1:"${port}" 2>/dev/null
• terminate_pids "${pid}"
• result=$(cat "${outfile}")
• rm -f "${outfile}"
• if [[ "${result}" == TEST ]]; then

• return 0
  

• fi
• return 1

+}

+test_ns_diff_global_to_local_loopback_local_fails() {

• init_namespaces
• if ! __test_loopback_two_netns "global0" "local0"; then

• return "${KSFT_PASS}"
  

• fi
• return "${KSFT_FAIL}"

+}

+test_ns_diff_local_to_global_loopback_fails() {

• init_namespaces
• if ! __test_loopback_two_netns "local0" "global0"; then

• return "${KSFT_PASS}"
  

• fi
• return "${KSFT_FAIL}"

+}

+test_ns_diff_local_to_local_loopback_fails() {

• init_namespaces
• if ! __test_loopback_two_netns "local0" "local1"; then

• return "${KSFT_PASS}"
  

• fi
• return "${KSFT_FAIL}"

+}

+test_ns_diff_global_to_global_loopback_ok() {

• init_namespaces
• if __test_loopback_two_netns "global0" "global1"; then

• return "${KSFT_PASS}"
  

• fi
• return "${KSFT_FAIL}"

+}

+test_ns_same_local_loopback_ok() {

• init_namespaces
• if __test_loopback_two_netns "local0" "local0"; then

• return "${KSFT_PASS}"
  

• fi
• return "${KSFT_FAIL}"

+}

+test_ns_same_local_host_connect_to_local_vm_ok() {

• local oops_before warn_before
• local ns="local0"
• local port=1234
• local dmesg_rc
• local pidfile
• local rc
• init_namespaces
• pidfile="$(create_pidfile)"
• if ! vm_start "${pidfile}" "${ns}"; then

• return "${KSFT_FAIL}"
  

• fi
• vm_wait_for_ssh "${ns}"
• oops_before=$(vm_dmesg_oops_count "${ns}")
• warn_before=$(vm_dmesg_warn_count "${ns}")
• vm_vsock_test "${ns}" "server" 2 "${TEST_GUEST_PORT}"
• # Skip test 29 (transport release use-after-free): This test attempts
• # binding both G2H and H2G CIDs. Because virtio-vsock (G2H) doesn't
• # support local namespaces the test will fail when
• # transport_g2h->stream_allow() returns false. This edge case only
• # happens for vsock_test in client mode on the host in a local
• # namespace. This is a false positive.
• host_vsock_test "${ns}" "127.0.0.1" "${VSOCK_CID}" "${TEST_HOST_PORT}" --skip=29
• rc=$?
• vm_dmesg_check "${pidfile}" "${ns}" "${oops_before}" "${warn_before}"
• dmesg_rc=$?
• terminate_pidfiles "${pidfile}"
• if [[ "${rc}" -ne 0 ]] || [[ "${dmesg_rc}" -ne 0 ]]; then

• return "${KSFT_FAIL}"
  

• fi
• return "${KSFT_PASS}"

+}

+test_ns_same_local_vm_connect_to_local_host_ok() {

• local oops_before warn_before
• local ns="local0"
• local port=1234
• local dmesg_rc
• local pidfile
• local rc
• init_namespaces
• pidfile="$(create_pidfile)"
• if ! vm_start "${pidfile}" "${ns}"; then

• return "${KSFT_FAIL}"
  

• fi
• vm_wait_for_ssh "${ns}"
• oops_before=$(vm_dmesg_oops_count "${ns}")
• warn_before=$(vm_dmesg_warn_count "${ns}")
• host_vsock_test "${ns}" "server" "${VSOCK_CID}" "${port}"
• vm_vsock_test "${ns}" "10.0.2.2" 2 "${port}"
• rc=$?
• vm_dmesg_check "${pidfile}" "${ns}" "${oops_before}" "${warn_before}"
• dmesg_rc=$?
• terminate_pidfiles "${pidfile}"
• if [[ "${rc}" -ne 0 ]] || [[ "${dmesg_rc}" -ne 0 ]]; then

• return "${KSFT_FAIL}"
  

• fi
• return "${KSFT_PASS}"

+}

namespaces_can_boot_same_cid() { local ns0=$1 local ns1=$2 @@ -869,6 +1432,7 @@ fi check_args "${ARGS[@]}" check_deps check_vng +check_socat handle_build

echo "1..${#ARGS[@]}"

-- 2.47.3