[Bug libfortran/92836] segfault with inquire()

[jvdelisle at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92836

Jerry DeLisle <jvdelisle at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jvdelisle at gcc dot gnu.org

--- Comment #3 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> ---
With the the following example I see varying results:

program inq
  use OMP_Lib
  implicit none
  logical :: s
  character(len=27) :: c
  integer :: i, j

  i=64
  !$omp parallel private(c,j,s)
  print *, OMP_Get_Thread_Num(), omp_get_num_threads(), omp_get_num_threads()/2
  do while (.true.)
     if (OMP_Get_Thread_Num() < omp_get_num_threads()/2) then
        open(newUnit=j,file='test.txt',form='formatted',status='unknown')
        write (c,'(e17.10, ">>>",i5, i5, "<<<")') 1.23456d0, j,
OMP_Get_Thread_Num()
        write (j,*) trim(c)
        close(j)
     else
        inquire(file='test.txt',exist=s)
     end if
  end do
  !$omp end parallel
end program

I get randomly:

$ ./a.out 
           0           8           4
           3           8           4
           6           8           4
           5           8           4
           4           8           4
           1           8           4
           2           8           4
At line 14 of file bug1.f90
At line 14 of file bug1.f90
           7           8           4
Fortran runtime error: Fortran runtime error: End of recordEnd of record

$ ./a.out 
           2           8           4
           5           8           4
           6           8           4
           1           8           4
           7           8           4
           0           8           4
           4           8           4
           3           8           4
At line 14 of file bug1.f90
At line 14 of file bug1.f90
At line 14 of file bug1.f90
At line 14 of file bug1.f90
Fortran runtime error: Fortran runtime error: Fortran runtime error: End of
recordFortran runtime error: End of recordEnd of record
End of record


[jerry@amdr threadbug]$ ./a.out 
           0           8           4
           2           8           4
           6           8           4
           1           8           4
           5           8           4
           7           8           4
At line 14 of file bug1.f90
Fortran runtime error: End of record
           3           8           4

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
$ ./a.out 
           2           8           4
           6           8           4
           1           8           4
           0           8           4
           5           8           4
           7           8           4
           3           8           4
           4           8           4
At line 14 of file bug1.f90
At line 14 of file bug1.f90
Fortran runtime error: At line 14 of file bug1.f90
At line 14 of file bug1.f90
End of recordFortran runtime error: Fortran runtime error: Fortran runtime
error: 
End of recordEnd of recordEnd of record


$ ./a.out 
           7           8           4
           6           8           4
           1           8           4
           0           8           4
           5           8           4
           2           8           4
           3           8           4
At line 14 of file bug1.f90
Fortran runtime error:            4           8           4
End of record
At line 14 of file bug1.f90
Fortran runtime error: End of file