t/concurrency/01-thread.t asan error

gistfile1.txt

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==9196==ERROR: AddressSanitizer: heap-use-after-free on address 0x618000285a88 at pc 0x7f1559cfe31c bp 0x7f15554fbea0 sp 0x7f15554fbe98
WRITE of size 8 at 0x618000285a88 thread T1
    #0 0x7f1559cfe31b in save_or_free_sim_stack /home/samantha/git/MoarVM/src/spesh/stats.c:508:37
    #1 0x7f1559cfe31b in MVM_spesh_stats_update /home/samantha/git/MoarVM/src/spesh/stats.c:649
    #2 0x7f1559cf632d in worker /home/samantha/git/MoarVM/src/spesh/worker.c:16:5
    #3 0x7f1559bd3705 in invoke_handler /home/samantha/git/MoarVM/src/6model/reprs/MVMCFunction.c:9:9
    #4 0x7f1559b0b7cd in thread_initial_invoke /home/samantha/git/MoarVM/src/core/threads.c:59:5
    #5 0x7f1559abe3e9 in MVM_interp_run /home/samantha/git/MoarVM/src/core/interp.c:92:5
    #6 0x7f1559b0aa43 in start_thread /home/samantha/git/MoarVM/src/core/threads.c:87:5
    #7 0x7f1558d8bac5  (/lib64/libpthread.so.0+0x7ac5)
    #8 0x7f15581408be in clone (/lib64/libc.so.6+0x1098be)

0x618000285a88 is located 520 bytes inside of 792-byte region [0x618000285880,0x618000285b98)
freed by thread T0 here:
    #0 0x4bc9e2 in __interceptor_free /var/tmp/portage/sys-libs/compiler-rt-sanitizers-6.0.0/work/compiler-rt-6.0.0.src/lib/asan/asan_malloc_linux.cc:68:3
    #1 0x7f1559adf4f3 in MVM_free /home/samantha/git/MoarVM/src/core/alloc.h:40:5
    #2 0x7f1559adf4f3 in MVM_tc_destroy /home/samantha/git/MoarVM/src/core/threadcontext.c:113
    #3 0x7f1559b65003 in run_gc /home/samantha/git/MoarVM/src/gc/orchestrate.c:220:13
    #4 0x7f1559b63db2 in MVM_gc_enter_from_allocator /home/samantha/git/MoarVM/src/gc/orchestrate.c:525:9
    #5 0x7f1559b0ad32 in try_join /home/samantha/git/MoarVM/src/core/threads.c:192:5
    #6 0x7f1559b0ad32 in MVM_thread_join /home/samantha/git/MoarVM/src/core/threads.c:198
    #7 0x7f1559acacfe in MVM_interp_run /home/samantha/git/MoarVM/src/core/interp.c:3669:17
    #8 0x7f1559dbe036 in MVM_vm_run_file /home/samantha/git/MoarVM/src/moar.c:412:5
    #9 0x4eaff1 in main /home/samantha/git/MoarVM/src/main.c:299:10
    #10 0x7f155805810c in __libc_start_main (/lib64/libc.so.6+0x2110c)

previously allocated by thread T0 here:
    #0 0x4bcf0a in calloc /var/tmp/portage/sys-libs/compiler-rt-sanitizers-6.0.0/work/compiler-rt-6.0.0.src/lib/asan/asan_malloc_linux.cc:97:3
    #1 0x7f1559aded82 in MVM_calloc /home/samantha/git/MoarVM/src/core/alloc.h:11:17
    #2 0x7f1559aded82 in MVM_tc_create /home/samantha/git/MoarVM/src/core/threadcontext.c:8
    #3 0x7f1559b09cc6 in MVM_thread_new /home/samantha/git/MoarVM/src/core/threads.c:29:5
    #4 0x7f1559acae12 in MVM_interp_run /home/samantha/git/MoarVM/src/core/interp.c:3664:40
    #5 0x7f1559dbe036 in MVM_vm_run_file /home/samantha/git/MoarVM/src/moar.c:412:5
    #6 0x4eaff1 in main /home/samantha/git/MoarVM/src/main.c:299:10
    #7 0x7f155805810c in __libc_start_main (/lib64/libc.so.6+0x2110c)

Thread T1 created by T0 here:
    #0 0x4a5cbd in __interceptor_pthread_create /var/tmp/portage/sys-libs/compiler-rt-sanitizers-6.0.0/work/compiler-rt-6.0.0.src/lib/asan/asan_interceptors.cc:204:3
    #1 0x7f1559e4abcc in uv_thread_create (//home/samantha/perl6/lib/libmoar.so+0xc9cbcc)
    #2 0x7f1559b0a69c in MVM_thread_run /home/samantha/git/MoarVM/src/core/threads.c:162:18
    #3 0x7f1559cf5ac4 in MVM_spesh_worker_setup /home/samantha/git/MoarVM/src/spesh/worker.c:156:9
    #4 0x7f1559dbce16 in MVM_vm_create_instance /home/samantha/git/MoarVM/src/moar.c:357:5
    #5 0x4eaec6 in main /home/samantha/git/MoarVM/src/main.c:274:18
    #6 0x7f155805810c in __libc_start_main (/lib64/libc.so.6+0x2110c)

SUMMARY: AddressSanitizer: heap-use-after-free /home/samantha/git/MoarVM/src/spesh/stats.c:508:37 in save_or_free_sim_stack
Shadow bytes around the buggy address:
  0x0c3080048b00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3080048b10: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c3080048b20: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c3080048b30: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c3080048b40: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
=>0x0c3080048b50: fd[fd]fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c3080048b60: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c3080048b70: fd fd fd fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3080048b80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3080048b90: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c3080048ba0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
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
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==9196==ABORTING