[Bug libfortran/119502] New: Runtime segfault when closing invalid unit

[anlauf at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119502

            Bug ID: 119502
           Summary: Runtime segfault when closing invalid unit
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libfortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: anlauf at gcc dot gnu.org
  Target Milestone: ---

The following code crashes with a segfault:

program foo
  integer :: iun = -1
  close (iun)
end

Excerpt from valgrind:

==28254== Process terminating with default action of signal 11 (SIGSEGV):
dumping core
==28254==    at 0x4A3E41C: __pthread_kill_implementation (in /lib64/libc.so.6)
==28254==    by 0x49EC841: raise (in /lib64/libc.so.6)
==28254==    by 0x49EC8FF: ??? (in /lib64/libc.so.6)
==28254==    by 0x40699B: _gfortrani_close_share (unix.c:1889)
==28254==    by 0x404060: _gfortran_st_close (close.c:87)

We could handle this more graciously...