https://rt.perl.org/Public/Bug/Display.html?id=126014

gistfile1.txt

dogbert@dogbert-VirtualBox ~/repos/rakudo $ ./perl6 -e '"x" xx 9999999999'
=================================================================
==585== ERROR: AddressSanitizer: heap-buffer-overflow on address 0xa6cff7fc at pc 0xb583c4d8 bp 0xbfed6b98 sp 0xbfed6b8c
WRITE of size 4 at 0xa6cff7fc thread T0
    #0 0xb583c4d7 in zero_slots /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:235
    #1 0xb583c4d7 in set_size_internal /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:338
    #2 0xb583c4d7 in set_elems /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:431
    #3 0xb5703ad0 in MVM_interp_run /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/interp.c:2302
    #4 0xb5a6ad32 in MVM_vm_run_file /home/dogbert/repos/rakudo/nqp/MoarVM/src/moar.c:309
    #5 0x80490e1 in main /home/dogbert/repos/rakudo/nqp/MoarVM/src/main.c:201
    #6 0xb53ccaf2 (/lib/i386-linux-gnu/libc.so.6+0x19af2)
    #7 0x8049233 in _start (/home/dogbert/repos/rakudo/install/bin/moar+0x8049233)
0xa6cff7fc is located 0 bytes to the right of 1345294332-byte region [0x56a06800,0xa6cff7fc)
allocated by thread T0 here:
    #0 0xb61de854 (/usr/lib/i386-linux-gnu/libasan.so.0+0x16854)
    #1 0xb583be1d in MVM_malloc /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/alloc.h:2
    #2 0xb583be1d in set_size_internal /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:334
    #3 0xb583be1d in set_elems /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:431
    #4 0xb5703ad0 in MVM_interp_run /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/interp.c:2302
    #5 0xb5a6ad32 in MVM_vm_run_file /home/dogbert/repos/rakudo/nqp/MoarVM/src/moar.c:309
    #6 0x80490e1 in main /home/dogbert/repos/rakudo/nqp/MoarVM/src/main.c:201
    #7 0xb53ccaf2 (/lib/i386-linux-gnu/libc.so.6+0x19af2)
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:247 zero_slots
Shadow bytes around the buggy address:
  0x34d9fea0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x34d9feb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x34d9fec0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x34d9fed0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x34d9fee0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x34d9fef0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00[04]
  0x34d9ff00:fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x34d9ff10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x34d9ff20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x34d9ff30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x34d9ff40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:     fa
  Heap righ redzone:     fb
  Freed Heap region:     fd
  Stack left redzone:    f1
  Stack mid redzone:     f2
  Stack right redzone:   f3
  Stack partial redzone: f4
  Stack after return:    f5
  Stack use after scope: f8
  Global redzone:        f9
  Global init order:     f6
  Poisoned by user:      f7
  ASan internal:         fe
==585== ABORTING