tests: Add post-analysis of selftest output to find real failures

debian/tests/selftests

@@ -46,7 +46,21 @@ if [ "$step" -ge 0 ]; then
 	# Enable testing CLONE_USERNS by unprivileged users
 	sysctl kernel.unprivileged_userns_clone=1
 
-	make -C tools/testing/selftests run_tests
+	# Some tests will write to stderr despite being successful,
+	# and the exit code from make will be 0 even if tests failed.
+	# So we have to do some post-analysis...
+	set -o pipefail
+	make -C tools/testing/selftests run_tests 2>&1 | tee $ADTTMP/log
+	set +o pipefail
+	if grep -E '\[(FAIL|UNSUPPORTED)\]|recipe for target .run_tests. failed' $ADTTMP/log | \
+	    grep -q -v \
+		 -e '^selftests: fw_userhelper.sh \[FAIL\]' \
+		 -e 'ftrace - function profiler with function tracing   \[UNSUPPORTED\]' \
+		 -e '^selftests: ftracetest \[FAIL\]' \
+		 -e '|| echo .*\[FAIL\]' \
+		 ; then
+	    echo >&2 "Unexpected failures found"
+	fi
     fi
 fi