MPI Fortran synchronizing data - arrays

Question

I have program that i working on parallelize using MPI. I have attached the test code, which breaks down the array into multiple segement along a given number of processor and then i am using broadcast to combine the results from all of the processes and give it out to all of the processes. The problem occurs when the distribution is not same along all of the processors and causes broadcast to fail. I have attached the following code that works with 6 processes, but not 8 processes.
program main
include 'mpif.h'
integer i, rank, nprocs, count, start, stop, nloops
integer err, n1
REAL srt, sp
REAL b(1,1:10242)
REAL c(1,1:10242)
integer, Allocatable :: jjsta(:), jjlen(:)
allocate (jjsta(0:nprocs-1),jjlen(0:nprocs-1))
call MPI_Init(ierr)
call MPI_Comm_rank(MPI_COMM_WORLD, rank, ierr)
call MPI_Comm_size(MPI_COMM_WORLD, nprocs, ierr)
n1 = 10242
call para_range(1,n1,nprocs,rank,start,stop)
jjsta(rank) = start
jjlen(rank) = stop -start +1
srt = MPI_WTIME()
do i=start,stop
c(1,i) = i
enddo
sp =MPI_WTIME()
print *,"Process ",rank," performed ", jjlen(rank), &
" iterations of the loop."
! CALL MPI_ALLGATHERV(c(1,jjsta(rank)), jjlen(rank), MPI_REAL,&
! b,jjlen(rank),jjsta(rank)+jjlen(rank)+1,MPI_REAL,MPI_COMM_WORLD,ierr)
CALL MPI_BCAST(c(1,jjsta(rank)), jjlen(rank), MPI_REAL,&
rank, MPI_COMM_WORLD, ierr)
call MPI_Finalize(ierr)
deallocate(jjsta,jjlen)
end program main
subroutine para_range(n1, n2, nprocs, irank, ista, iend)
integer(4) :: n1 ! Lowest value of iteration variable
integer(4) :: n2 ! Highest value of iteration variable
integer(4) :: nprocs ! # cores
integer(4) :: irank ! Iproc (rank)
integer(4) :: ista ! Start of iterations for rank iproc
integer(4) :: iend ! End of iterations for rank iproc
iwork1 = ( n2 -n1 + 1 ) / nprocs
! print *, iwork1
iwork2 = MOD(n2 -n1 + 1, nprocs)
! print *, iwork2
ista = irank* iwork1 + n1 + MIN(irank, iwork2)
iend = ista + iwork1 -1
if (iwork2 > irank) iend = iend + 1
return
end subroutine para_range
and when i run it with 8 processors with MPI_Bcast commented out and this is what it prints out this and it works
Process 2 performed 1280 iterations of the loop.
Process 1 performed 1281 iterations of the loop.
Process 4 performed 1280 iterations of the loop.
Process 5 performed 1280 iterations of the loop.
Process 3 performed 1280 iterations of the loop.
Process 6 performed 1280 iterations of the loop.
Process 0 performed 1281 iterations of the loop.
Process 7 performed 1280 iterations of the loop.
But when i try to combine all of the results and broadcast that this is the error i get
Fatal error in MPI_Bcast:
Message truncated, error stack:
MPI_Bcast(1128)...................: MPI_Bcast(buf=0x2af182d8d028, count=1280, MPI_REAL, root=4, MPI_COMM_WORLD) failed
knomial_2level_Bcast(1268)........:
MPIDI_CH3U_Receive_data_found(259): Message from rank 0 and tag 2 truncated; 5124 bytes received but buffer size is 5120
Process 4 performed 1280 iterations of the loop.
I also tried the MPI_Allgatherv to combine the result in array b and i get the following error:
Fatal error in MPI_Allgatherv:
Message truncated, error stack:
MPI_Allgatherv(1050)................: MPI_Allgatherv(sbuf=0x635df8, scount=1280, MPI_REAL, rbuf=0x62bde8, rcounts=0x2b3ff297b244, displs=0x7fff3ebc1fb0, MPI_REAL, MPI_COMM_WORLD) failed
MPIR_Allgatherv(243)................:
MPIC_Sendrecv(117)..................:
MPIDI_CH3U_Request_unpack_uebuf(631): Message truncated; 5124 bytes received but buffer size is 5120
The problem when combining the arrays to me seems like that it is not updating the length of the array being sent. I can't seem to figure out how to solve the problem any help would be appreciated. Thank you.