(gdb) bt 16
#0  terminate_due_to_signal (sig=6, backtrace_limit=40) at ../../src/emacs.c:364
#1  0x00000000005aa0c9 in emacs_abort () at ../../src/sysdep.c:2426
#2  0x0000000000612e7a in mark_object (arg=XIL(0x301c719)) at ../../src/alloc.c:6677
#3  0x0000000000613079 in mark_object (arg=XIL(0x355a503)) at ../../src/alloc.c:6730
#4  0x0000000000613079 in mark_object (arg=XIL(0x355a493)) at ../../src/alloc.c:6730
#5  0x000000000060f229 in mark_maybe_object (obj=XIL(0x355a493)) at ../../src/alloc.c:4846
#6  0x000000000060f4b9 in mark_memory (start=0x7fffffff21e0, end=0x7fffffffe8c8)
    at ../../src/alloc.c:4990
#7  0x000000000060f4ee in mark_stack (bottom=0x7fffffffe8c8 "a\036h\364\377\177", 
    end=0x7fffffff21e0 "\360!\377\377\377\177") at ../../src/alloc.c:5197
#8  0x00000000006cddb3 in mark_one_thread (thread=0xe103e0 <main_thread>) at ../../src/thread.c:616
#9  0x00000000006cdf48 in mark_threads_callback (ignore=0x0) at ../../src/thread.c:649
#10 0x000000000060f535 in flush_stack_call_func (func=0x6cdeb5 <mark_threads_callback>, arg=0x0)
    at ../../src/alloc.c:5224
#11 0x00000000006cdf7a in mark_threads () at ../../src/thread.c:656
#12 0x0000000000611502 in garbage_collect_1 (end=0x7fffffff23c0) at ../../src/alloc.c:6001
#13 0x0000000000611bef in Fgarbage_collect () at ../../src/alloc.c:6172
#14 0x00000000005799f8 in maybe_gc () at ../../src/lisp.h:4748
#15 0x000000000063c326 in Ffuncall (nargs=3, args=0x7fffffff2478) at ../../src/eval.c:2751
(More stack frames follow...)
(gdb) xbacktrace
"Automatic GC" (0x0)
"mapcar" (0xffff2480)
"yas-active-snippets" (0xffff2958)
"yas--place-overlays" (0xffff2e40)
"yas--move-to-field" (0xffff33d0)
0x320a050 PVEC_COMPILED
"funcall" (0xffff3860)
"let" (0xffff3b30)
"eval" (0xffff3cf0)
"yas-expand-snippet" (0xffff4410)
"yas--expand-or-prompt-for-template" (0xffff4910)
"yas-expand" (0xffff4da0)
"save-restriction" (0xffff5060)
"save-current-buffer" (0xffff51e0)
"update-fn" (0xffff53c0)
"ivy--insert-minibuffer" (0xffff58a0)
"ivy--exhibit" (0xffff5e70)
"ivy--queue-exhibit" (0xffff6340)
"execute-kbd-macro" (0xffff66e0)
"progn" (0xffff6880)
"if" (0xffff69e0)
"while" (0xffff6b90)
"let" (0xffff6db0)
0x3407a30 Lisp type 3
"apply" (0xffff7118)
"timer-event-handler" (0xffff7688)
"input-pending-p" (0xffff7988)
"sit-for" (0xffff7e80)
"yas-expand-snippet" (0xffff85a0)
"yas--expand-or-prompt-for-template" (0xffff8aa0)
"yas-expand" (0xffff8f30)
"save-restriction" (0xffff91f0)
"save-current-buffer" (0xffff9370)
"update-fn" (0xffff9550)
"ivy--insert-minibuffer" (0xffff9a30)
"ivy--exhibit" (0xffffa000)
"ivy--minibuffer-setup" (0xffffa510)
0x36bb630 PVEC_COMPILED
"read-from-minibuffer" (0xffffae58)
"ivy-read" (0xffffb5f0)
"condition-case" (0xffffb990)
"catch" (0xffffbb60)
"while" (0xffffbd10)
"let" (0xffffbf30)
"let" (0xffffc150)
"eval-buffer" (0xffffc440)
"load-with-code-conversion" (0xffffc9c8)
"load" (0xffffcd40)
0xad83e0 PVEC_COMPILED
"command-line" (0xffffdeb8)
"normal-top-level" (0xffffe4e0)
(gdb) frame 5
#5  0x000000000060f229 in mark_maybe_object (obj=XIL(0x355a493)) at ../../src/alloc.c:4846
4846		mark_object (obj);
(gdb) p obj
$100 = XIL(0x355a493)
(gdb) xxlist
Lisp_Cons:(Lisp_String:" " . Lisp_Int0:-36)
Lisp_Cons:(Lisp_Misc_Marker . Lisp_Int1:-1)
Lisp_Cons:(Lisp_Misc_Free . Lisp_Int1:1)
Lisp_Cons:(Lisp_Misc_Overlay . Lisp_Int1:1)
Lisp_Cons:(Lisp_Int0:4 . Lisp_Int0:36)
Lisp_Cons:(Lisp_String:"ah" . Lisp_Int0:4)
Lisp_Cons:(Lisp_Int1:3 . Lisp_Int0:6)
Lisp_Symbol:"nil"
Lisp_Cons:(Lisp_Symbol:"apply" Lisp_Symbol:"yas--take-care-of-redo" Lisp_Vectorlike: . Lisp_Symbol
:"nil")
Lisp_Cons:(Lisp_Int0:4 . Lisp_Int0:10)
Lisp_Cons:(Lisp_String:"a" . Lisp_Int0:4)
Lisp_Cons:(Lisp_Int1:3 . Lisp_Int1:5)
Lisp_Cons:(Lisp_Symbol:"apply" Lisp_Symbol:"yas--take-care-of-redo" Lisp_Vectorlike: . Lisp_Symbol
:"nil")
Lisp_Cons:(Lisp_Int0:4 . Lisp_Int0:10)
Lisp_Cons:(Lisp_String:"a" . Lisp_Int0:4)
Lisp_Cons:(Lisp_Int1:3 . Lisp_Int1:5)
Lisp_Symbol:"nil"
Lisp_Cons:(Lisp_Symbol:"apply" Lisp_Symbol:"yas--take-care-of-redo" Lisp_Vectorlike: . Lisp_Symbol
:"nil")
Lisp_Cons:(Lisp_String:" " . Lisp_Int0:-36)
Lisp_Cons:(Lisp_Misc_Marker . Lisp_Int1:-1)
...