Protect test info access with mutex

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/tests/suites/host_test.function b/tests/suites/host_test.function
index 1ebaf46..eb42a07 100644
--- a/tests/suites/host_test.function
+++ b/tests/suites/host_test.function
@@ -720,6 +720,8 @@
                     mbedtls_fprintf(stdout, "----\n");
                     total_skipped++;
                 } else {
+                    char line_buffer[MBEDTLS_TEST_LINE_LENGTH];
+
                     total_errors++;
                     mbedtls_fprintf(stdout, "FAILED\n");
                     mbedtls_fprintf(stdout, "  %s\n  at ",
@@ -731,13 +733,14 @@
                     mbedtls_fprintf(stdout, "line %d, %s",
                                     mbedtls_test_get_line_no(),
                                     mbedtls_get_test_filename());
-                    if (mbedtls_test_get_line1()[0] != 0) {
-                        mbedtls_fprintf(stdout, "\n  %s",
-                                        mbedtls_test_get_line1());
+
+                    mbedtls_test_get_line1(line_buffer);
+                    if (line_buffer[0] != 0) {
+                        mbedtls_fprintf(stdout, "\n  %s", line_buffer);
                     }
-                    if (mbedtls_test_get_line2()[0] != 0) {
-                        mbedtls_fprintf(stdout, "\n  %s",
-                                        mbedtls_test_get_line2());
+                    mbedtls_test_get_line2(line_buffer);
+                    if (line_buffer[0] != 0) {
+                        mbedtls_fprintf(stdout, "\n  %s", line_buffer);
                     }
                 }
                 fflush(stdout);