MasterDuke's example causing a SEGV

gistfile1.txt

dogbert@dogbert-VirtualBox:~/repos/rakudo$ ASAN_OPTIONS=detect_leaks=false ./rakudo-m -e 'my $t = ("errors.md.tmpl" xx 1_000).join(" foo "); race for ^2_000 { my $page = $t; $page ~~ s:g[ "foo" ] = "a"; }'
AddressSanitizer:DEADLYSIGNAL
=================================================================
==182115==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f0dfce351d1 bp 0x7f0dec8073a0 sp 0x7f0dec807230 T6)
==182115==The signal is caused by a READ memory access.
==182115==Hint: address points to the zero page.
    #0 0x7f0dfce351d0 in MVM_gc_write_barrier src/gc/wb.h:10
    #1 0x7f0dfce351d0 in MVM_gc_write_barrier src/gc/wb.h:9
    #2 0x7f0dfce351d0 in log_param_type src/spesh/log.c:87
    #3 0x7f0dfce351d0 in log_parameter src/spesh/log.c:96
    #4 0x7f0dfce351d0 in MVM_spesh_log_entry src/spesh/log.c:130
    #5 0x7f0dfcbe43db in MVM_frame_dispatch src/core/frame.c:575
    #6 0x7f0dfcdcbcf5 in MVM_disp_program_run src/disp/program.c:3583
    #7 0x7f0dfcdab317 in dispatch_monomorphic src/disp/inline_cache.c:107
    #8 0x7f0dfcb89888 in MVM_interp_run src/core/interp.c:5379
    #9 0x7f0dfcc06439 in start_thread src/core/threads.c:101
    #10 0x7f0dfc248608 in start_thread /build/glibc-YbNSs7/glibc-2.31/nptl/pthread_create.c:477
    #11 0x7f0dfc395292 in __clone (/lib/x86_64-linux-gnu/libc.so.6+0x122292)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV src/gc/wb.h:10 in MVM_gc_write_barrier
Thread T6 created by T3 here:
    #0 0x7f0dfde58805 in pthread_create (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x3a805)
    #1 0x7f0dfd03c5d4 in uv_thread_create_ex (//home/dogbert/repos/rakudo/nqp/MoarVM/../../install/lib/libmoar.so+0xbd75d4)

Thread T3 created by T0 here:
    #0 0x7f0dfde58805 in pthread_create (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x3a805)
    #1 0x7f0dfd03c5d4 in uv_thread_create_ex (//home/dogbert/repos/rakudo/nqp/MoarVM/../../install/lib/libmoar.so+0xbd75d4)

==182115==ABORTING