Selftests are supposed to run on any kernels, including the old ones not
supporting all MPTCP features.

One of them is the new listener events linked to the path-manager
introduced by commit f8c9dfbd875b ("mptcp: add pm listener events").

It is possible to look for "mptcp_event_pm_listener" in kallsyms to know
in advance if the kernel supports this feature and skip these sub-tests
if the feature is not supported.

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/368
Fixes: 6c73008aa301 ("selftests: mptcp: listener test for userspace PM")
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
---
 tools/testing/selftests/net/mptcp/userspace_pm.sh | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/testing/selftests/net/mptcp/userspace_pm.sh b/tools/testing/selftests/net/mptcp/userspace_pm.sh
index 38a1d34f7b4d..98d9e4d2d3fc 100755
--- a/tools/testing/selftests/net/mptcp/userspace_pm.sh
+++ b/tools/testing/selftests/net/mptcp/userspace_pm.sh
@@ -4,6 +4,7 @@
 . "$(dirname "${0}")/mptcp_lib.sh"
 
 mptcp_lib_check_mptcp
+mptcp_lib_check_kallsyms
 
 if ! mptcp_lib_has_file '/proc/sys/net/mptcp/pm_type'; then
 	echo "userspace pm tests are not supported by the kernel: SKIP"
@@ -914,6 +915,11 @@ test_listener()
 {
 	print_title "Listener tests"
 
+	if ! mptcp_lib_kallsyms_has "mptcp_event_pm_listener$"; then
+		stdbuf -o0 -e0 printf "LISTENER events                                            \t[SKIP] Not supported\n"
+		return
+	fi
+
 	# Capture events on the network namespace running the client
 	:>$client_evts
 

-- 
2.39.2