Segfault in NRT from use of generator

[stuartarchibald]

Reporting a bug

• I am using the latest released version of Numba (most recent is visible in
  the change log (https://github.com/numba/numba/blob/master/CHANGE_LOG).
• I have included below a minimal working reproducer (if you are unsure how
  to write one see http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports).

Reported on gitter by @igorghi:

import numba
import numpy as np
 
@numba.njit
def comb_2_gen_numba_test(arr, n_batch):
    n = arr.shape[0]
    batch = np.zeros((n_batch,2),dtype=np.int32)
    c=0
    for i in range(n-1):
        for k in range(i+1,n):
            batch[c,0] = arr[i]
            batch[c,1] = arr[k]
            c+=1  
            if c%n_batch == 0:
                c=0
                yield batch
               
               
a = comb_2_gen_numba_test(np.arange(4),2)
 
for elem in a:
    print(elem)

this segfaults. Doing gdb -ex r -ex bt --args python gi6.py gives:

Program received signal SIGABRT, Aborted.
0x00007ffff7828277 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
56        return INLINE_SYSCALL (tgkill, 3, pid, selftid, sig);
#0  0x00007ffff7828277 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1  0x00007ffff7829968 in __GI_abort () at abort.c:90
#2  0x00007ffff786ad37 in __libc_message (do_abort=do_abort@entry=2, 
    fmt=fmt@entry=0x7ffff797cd58 "*** Error in `%s': %s: 0x%s ***\n") at ../sysdeps/unix/sysv/linux/libc_fatal.c:196
#3  0x00007ffff7873499 in malloc_printerr (ar_ptr=0x7ffff7bb8760 <main_arena>, ptr=<optimized out>, 
    str=0x7ffff797ce18 "double free or corruption (fasttop)", action=3) at malloc.c:5025
#4  _int_free (av=0x7ffff7bb8760 <main_arena>, p=<optimized out>, have_lock=0) at malloc.c:3847
#5  0x00007fffdecc6fbe in NRT_MemInfo_call_dtor ()
   from <numba_path>/numba/runtime/_nrt_python.cpython-36m-x86_64-linux-gnu.so
#6  0x00007fffdecc58bd in MemInfo_dealloc ()
   from <numba_path>/numba/runtime/_nrt_python.cpython-36m-x86_64-linux-gnu.so
#7  0x00007fffeabfb919 in array_dealloc ()
   from <env_path>/lib/python3.6/site-packages/numpy/core/multiarray.cpython-36m-x86_64-linux-gnu.so
#8  0x00005555556f26f8 in call_function ()
#9  0x0000555555714cba in _PyEval_EvalFrameDefault ()
#10 0x00005555556ed459 in PyEval_EvalCodeEx ()
#11 0x00005555556ee1ec in PyEval_EvalCode ()
#12 0x00005555557689a4 in run_mod ()
#13 0x0000555555768da1 in PyRun_FileExFlags ()
#14 0x0000555555768fa4 in PyRun_SimpleFileExFlags ()
#15 0x000055555576ca9e in Py_Main ()
#16 0x00005555556344be in main ()