[PATCH mptcp-next v2] Squash-to: "selftests: mptcp: tweak simult_flows for debug kernels"

[Mat Martineau <mathew.j.martineau@linux.intel.com>]

kbuild is still seeing intermittent failures in the simult_flows.sh
test. It uses a kernel config without kmemleak, but with other
performance-affecting debug options like lockdep and kasan.

Example failures:
kernel-selftests.net/mptcp.simult_flows.sh.unbalanced_bwidth_with_unbalanced_delay_transfer_slower_than_expected!_runtime_4339_ms_expected_4005_ms_max_4005.fail
kernel-selftests.net/mptcp.simult_flows.sh.unbalanced_bwidth_transfer_slower_than_expected!_runtime_4285_ms_expected_4005_ms_max_4005.fail
kernel-selftests.net/mptcp.simult_flows.sh.unbalanced_bwidth_transfer_slower_than_expected!_runtime_4346_ms_expected_4005_ms_max_4005.fail

Adjust the debug detection to look for more kernel debug features and
further loosen the simult_flows timing constraints if any of those
features are detected.

v2: Use kallsyms for debug feature detection, increase the debug timeout.

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 tools/testing/selftests/net/mptcp/simult_flows.sh | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/simult_flows.sh b/tools/testing/selftests/net/mptcp/simult_flows.sh
index e266b26a4274..ffa13a957a36 100755
--- a/tools/testing/selftests/net/mptcp/simult_flows.sh
+++ b/tools/testing/selftests/net/mptcp/simult_flows.sh
@@ -110,9 +110,12 @@ setup()
 	# debug build can slow down measurably the test program
 	# we use quite tight time limit on the run-time, to ensure
 	# maximum B/W usage.
-	# Use the kmemleak file presence as a rough estimate for this being
-	# a debug kernel and increase the maximum run-time accordingly
-	[ -f /sys/kernel/debug/kmemleak ] && slack=$((slack+200))
+	# Use kmemleak/lockdep/kasan/prove_locking presence as a rough
+	# estimate for this being a debug kernel and increase the
+	# maximum run-time accordingly. Observed run times for CI builds
+	# running selftests, including kbuild, were used to determine the
+	# amount of time to add.
+	grep -q ' kmemleak_init$\| lockdep_init$\| kasan_init$\| prove_locking$' /proc/kallsyms && slack=$((slack+550))
 }
 
 # $1: ns, $2: port
-- 
2.37.0