By default, the ASAN message goes to STDERR. This causes problem if we cannot
log the ASAN message, and we can not figure out why the ASAN check fails.
This change set the ASAN message goes to /va/log/asan${pid} by default.
--- a/compiler-rt/lib/sanitizer_common/sanitizer_flags.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_flags.inc
@@ -52,7 +52,7 @@ COMMON_FLAG(bool, handle_ioctl, false, "Intercept and handle ioctl requests.")
 COMMON_FLAG(int, malloc_context_size, 1,
             "Max number of stack frames kept for each allocation/deallocation.")
 COMMON_FLAG(
-    const char *, log_path, nullptr,
+    const char *, log_path, "/var/log/asan/asan",
     "Write logs to \"log_path.pid\". The special values are \"stdout\" and "
     "\"stderr\". If unspecified, defaults to \"stderr\".")
 COMMON_FLAG(