[SOLVED] DEALLOCATE statement in Gfortran kills a program. Why?

AlexBB · 03-27-2015, 11:50 AM

I have this main in Gfortran. It works perfectly with one problem. If I include DEALLOCATE the program craches. In this particular configuration this problem is not lethal. By the time of the crash all execution is done and I usually simply comment this statement out, however, in real life it will be a serious problem. The main will eventually be converted into a subroutine with a loop and the memory will be allocated and deallocated many times. What is the problem? This is the code:

Code:

program main
   use fft_vect_mod    ! must also be in every procedure without exceptions.
   implicit none   
   DOUBLE COMPLEX, DIMENSION (:), POINTER :: Input 
   DOUBLE COMPLEX, DIMENSION (:), POINTER :: Output  
   DOUBLE COMPLEX :: yy
   integer :: N = 1024, jj = 1, sv
   REAL*8 :: xx, blackmanHarrisWindow  
   ALLOCATE (Input(N),Output(N))
   open (unit=1,file="cppFFTinp.dat",status="old")
   open (unit=2,file="cppFFTout.dat",status="old")
   open (unit=3,file="cppFFTcoef.dat",status="old")
   do while (jj < N)
     xx = blackmanHarrisWindow (jj,N)
     yy = CMPLX (xx,0.0D0)     
     Input(jj) = yy
     write (1,*) DBLE (Input(jj))      
     jj = jj + 1
   enddo   
   call Forward (Input, Output, N)
   jj = 1
   do while (jj < N)
     write (3,*) DBLE (Output(jj))
     jj = jj + 1
   enddo
   call Inverse (Output, Input, N, .true.)
   jj = 1
   do while (jj < N)
     write (2,*) DBLE (Input(jj))
     jj = jj + 1
   enddo
   close (unit=1)
   close (unit=2)
   close (unit=3)
   DEALLOCATE (Input,Output,STAT=sv)
 end program main

and this is the core dump:

Code:

./a.out
*** glibc detected *** ./a.out: double free or corruption (!prev): 0x0940fc18 ***
======= Backtrace: =========
/lib/i386-linux-gnu/libc.so.6(+0x75ee2)[0xb74f2ee2]
./a.out[0x8049045]
./a.out[0x80490d6]
/lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf3)[0xb74964d3]
./a.out[0x8048741]
======= Memory map: ========
08048000-0804a000 r-xp 00000000 08:01 10747909   /home/alex/GFORTRAN-APPS/FFT/LIBROW-FFT/a.out
0804a000-0804b000 r--p 00001000 08:01 10747909   /home/alex/GFORTRAN-APPS/FFT/LIBROW-FFT/a.out
0804b000-0804c000 rw-p 00002000 08:01 10747909   /home/alex/GFORTRAN-APPS/FFT/LIBROW-FFT/a.out
0940e000-0942f000 rw-p 00000000 00:00 0          [heap]
b73d7000-b73f3000 r-xp 00000000 08:01 525207     /lib/i386-linux-gnu/libgcc_s.so.1
b73f3000-b73f4000 r--p 0001b000 08:01 525207     /lib/i386-linux-gnu/libgcc_s.so.1
b73f4000-b73f5000 rw-p 0001c000 08:01 525207     /lib/i386-linux-gnu/libgcc_s.so.1
b7408000-b7409000 rw-p 00000000 00:00 0 
b7409000-b747b000 r-xp 00000000 08:01 6820765    /usr/lib/i386-linux-gnu/libquadmath.so.0.0.0
b747b000-b747c000 r--p 00071000 08:01 6820765    /usr/lib/i386-linux-gnu/libquadmath.so.0.0.0
b747c000-b747d000 rw-p 00072000 08:01 6820765    /usr/lib/i386-linux-gnu/libquadmath.so.0.0.0
b747d000-b7620000 r-xp 00000000 08:01 525186     /lib/i386-linux-gnu/libc-2.15.so
b7620000-b7622000 r--p 001a3000 08:01 525186     /lib/i386-linux-gnu/libc-2.15.so
b7622000-b7623000 rw-p 001a5000 08:01 525186     /lib/i386-linux-gnu/libc-2.15.so
b7623000-b7627000 rw-p 00000000 00:00 0 
b7627000-b7651000 r-xp 00000000 08:01 525218     /lib/i386-linux-gnu/libm-2.15.so
b7651000-b7652000 r--p 00029000 08:01 525218     /lib/i386-linux-gnu/libm-2.15.so
b7652000-b7653000 rw-p 0002a000 08:01 525218     /lib/i386-linux-gnu/libm-2.15.so
b7653000-b7751000 r-xp 00000000 08:01 6815786    /usr/lib/i386-linux-gnu/libgfortran.so.3.0.0
b7751000-b7752000 r--p 000fe000 08:01 6815786    /usr/lib/i386-linux-gnu/libgfortran.so.3.0.0
b7752000-b7753000 rw-p 000ff000 08:01 6815786    /usr/lib/i386-linux-gnu/libgfortran.so.3.0.0
b7753000-b7754000 rw-p 00000000 00:00 0 
b7766000-b7769000 rw-p 00000000 00:00 0 
b7769000-b776a000 r-xp 00000000 00:00 0          [vdso]
b776a000-b778a000 r-xp 00000000 08:01 525166     /lib/i386-linux-gnu/ld-2.15.so
b778a000-b778b000 r--p 0001f000 08:01 525166     /lib/i386-linux-gnu/ld-2.15.so
b778b000-b778c000 rw-p 00020000 08:01 525166     /lib/i386-linux-gnu/ld-2.15.so
bfca3000-bfcc4000 rw-p 00000000 00:00 0          [stack]
Aborted (core dumped)

estabroo · 03-27-2015, 03:03 PM

Have you tried making them ALLOCATABLE instead of POINTER?

Code:

   DOUBLE COMPLEX, DIMENSION (:), ALLOCATABLE :: Input 
   DOUBLE COMPLEX, DIMENSION (:), ALLOCATABLE :: Output

AlexBB · 03-27-2015, 03:32 PM

Yes, I've tried. Something went wrong and it either did not compile or somehow it did not work, I now don't remember. Could be that it compiled but crashed on execution. The thing is this POINTER variant does work in everything except DEALLOCATE and it is very comforting.

AlexBB · 03-29-2015, 03:30 PM

estabroo, I just tried ALLOCATABLE without pointers and it worked with DEALLOCATE perfectly well.

Thanks, - Alex