https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113005
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Execution timeout is: 300 spawn [open ...] STOP 2 Internal Error: Trying to free nonempty asynchronous unit Error termination. Backtrace: Internal Error: Trying to free nonempty asynchronous unit Error termination. Backtrace: #0 0x7f986429289e in free_async_unit at ../../../libgfortran/io/async.c:211 #1 0x7f9864288729 in close_unit_1 at ../../../libgfortran/io/unit.c:759 #2 0x401644 in ??? #3 0x7f986432cd7d in ??? #4 0x7f9863e87c90 in ??? #5 0x7f9863f07fbb in ??? #6 0xffffffffffffffff in ??? FAIL: libgomp.fortran/rwlock_1.f90 -O0 execution test is what I see in the log. Or just STOP 2.