If I understand correctly, the following situation:

jenkins@ff742997f986:~$ echo "int main() { return 0; }" > test.c
jenkins@ff742997f986:~$ clang-5.0 -fsanitize=address test.c
jenkins@ff742997f986:~$ ./a.out 
==4821==LeakSanitizer has encountered a fatal error.
==4821==HINT: For debugging, try setting environment variable LSAN_OPTIONS=verbosity=1:log_threads=1
==4821==HINT: LeakSanitizer does not work under ptrace (strace, gdb, etc)

occurs whenever you don't have ptrace rights, e.g., if ptrace is disabled or you're working inside a Docker image. It would be much better if LeakSanitizer could detect if this is the trace, and turn itself off automatically (maybe with a warning.) Or, if not that, mention this as another possible explanation. Or also suggest how to turn off LeakSanitizer manually with ASAN_OPTIONS.