Intel Fortran error "allocatable array or pointer is not allocated"

When I tried to run a huge Fortran code (the code is compiled using Intel compiler version 13.1.3.192), it gave me error message like this:

... 
Info[FDFI_Setup]: HPDF code version number is  1.00246
forrtl: severe (153): allocatable array or pointer is not allocated
Image              PC                Routine            Line        Source
arts               0000000002AD96BE  Unknown               Unknown  Unknown
arts               0000000002AD8156  Unknown               Unknown  Unknown
arts               0000000002A87532  Unknown               Unknown  Unknown
...

Nonetheless, if I insert a small write statement (which is just to check the code, not to disturb the original purpose of the code) in one of the subroutines as the following (I couldn't put all the codes since they are too huge):

    ...
    endif
    call GetInputLine(Unit,line,eof,err)
  enddo

  if(err) return

  ! - [elfsummer] 20140815 Checkpoint 23
  open(unit = 1, file = '/bin/monitor/log_checkpoint',status='old',position='append')
  write(1,*) "BEFORE checking required keys: so far so good!"
  close(1)

  ! check required keys
  ! for modes = 2,3, P and T are the required keys
  if(StrmDat%ModeCI==2.or.StrmDat%ModeCI==3) then
  ...

then suddenly, the error message shown above disappears and the code can run correctly! I also tried to insert such write statements in other locations in the source code but the above error message still exists.

According to Intel's documentation:

severe (153): Allocatable array or pointer is not allocated FOR$IOS_INVDEALLOC. A Fortran 90 allocatable array or pointer must already be allocated when you attempt to deallocate it. You must allocate the array or pointer before it can again be deallocated. Note: This error can be returned by STAT in a DEALLOCATE statement.

However, I couldn't see any relations between the error and the "write statements" I added to the code. There is no such "allocate" command in the location I add the write statements.

So I am quite confused. Does anybody know the reasons? Any help is greatly appreciated!!

With traceback option, I could locate the error source directly:

    subroutine StringRead(Str,delimiter,StrArray,ns)   ! [private] read strings separated by    delimiter
    implicit none
    character*(*),intent(in)    :: Str
    character*(*),intent(in)    :: delimiter
    character*(*),pointer       :: StrArray(:)
    integer,intent(out)         :: ns
! - local variables
    character(len=len(Str))     :: tline
    integer                     :: nvalue,nvalue_max
    character(len=len(StrArray)),pointer:: sarray(:),sarray_bak(:)
    integer                     :: len_a,len_d,i

    ! deallocate StrArray
    if(associated(StrArray)) deallocate(StrArray)

The error, according to the information the traceback gave me, lies in the last statement shown above. If I comment out this statement, then the "forrtl: severe (153)" error would disappear while new errors being generated... But still, I don't think this statement itself could go wrong...It acts as if it just ignores the if... condition and directly reads the deallocate commend, which seems weird to me.

Solution

You could have a bug in which you are illegally writing to memory and damaging the structure that stores the allocation information. Changing the code might cause the memory damage to occur elsewhere and that specific error to disappear. Generally, illegal memory accesses typically occur two ways in Fortran. 1) illegal subscripts, 2) mismatch between actual and dummy arguments, i.e., between variables in call and variables as declared in procedures. You can search for the first type of error by using your compiler's option for run-time subscript checking. You can guard against the second by placing all of your procedures in modules and useing those modules so that the compiler can check for argument consistency.