[Bug libfortran/25835] New: Segfault or Bad Address error on unformatted sequential READ

[jvdelisle at gcc dot gnu dot org]

This PR is branched from PR25697 and appears to be a problem in fd_alloc
related to setting s->active = 0 when it should not for buffer sizes greater
than 8192 bytes.  The following test case appears to not fail when the data
array is 2044 elements ans gives a runtime when 2045.  This is the 8192 byte
crossover point (2044 x 4 + 16 for record markers)

The test case also involves EOF conditions.

      integer data(2045)
      do i = 1,2045
        data(i)=-2
      enddo
      open(unit=11,status='scratch',form='unformatted')
       write(11)data
       read(11,end=        1000 )data
       call abort()
 1000  continue
       print *, "First read done."
       backspace 11
       backspace 11
       read(11,end=        1001 )data
       print *, "Second read normal exit."
 1001  continue
       read(11,end=        1002 )data
       call abort()
 1002  continue
       print *, "Third read done."
       close(11)
       end


-- 
           Summary: Segfault or Bad Address error on unformatted sequential
                    READ
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libfortran
        AssignedTo: jvdelisle at gcc dot gnu dot org
        ReportedBy: jvdelisle at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25835