I was about to say that here's the original thread:
https://lists.nongnu.org/archive/html/qemu-devel/2021-10/msg01972.html
and here's the backtrace:
#0 acpi_pm1_cnt_write (val=40, ar=0x55555695f340) at ../hw/acpi/core.c:556
#1 acpi_pm_cnt_write (opaque=0x55555695f340, addr=1, val=40, width=2)
at ../hw/acpi/core.c:602
#2 0x0000555555b3a82f in memory_region_write_accessor
(mr=mr@entry=0x55555695f590, addr=1,
value=value@entry=0x7fffefffdd08, size=size@entry=2, shift=<optimized
out>, mask=mask@entry=65535, attrs=...)
at ../softmmu/memory.c:492
#3 0x0000555555b3813e in access_with_adjusted_size
(addr=addr@entry=1, value=value@entry=0x7fffefffdd08,
size=size@entry=1, access_size_min=<optimized out>,
access_size_max=<optimized out>, access_fn=
0x555555b3a7b0 <memory_region_write_accessor>, mr=0x55555695f590,
attrs=...) at ../softmmu/memory.c:554
#4 0x0000555555b3c449 in memory_region_dispatch_write
(mr=mr@entry=0x55555695f590, addr=1, data=<optimized out>, op=<optimized
out>, attrs=attrs@entry=...)
at ../softmmu/memory.c:1511
#5 0x0000555555b2c121 in flatview_write_continue
(fv=fv@entry=0x7fff84d23b30, addr=addr@entry=4261416709,
attrs=attrs@entry=..., ptr=ptr@entry=0x7fffefffdec0, len=len@entry=1,
addr1=<optimized out>,
l=<optimized out>, mr=0x55555695f590) at host-utils.h:165
#6 0x0000555555b2c399 in flatview_write (len=1, buf=0x7fffefffdec0,
attrs=..., addr=4261416709, fv=0x7fff84d23b30) at
../softmmu/physmem.c:2822
#7 subpage_write (opaque=<optimized out>, addr=<optimized out>,
value=<optimized out>, len=1, attrs=...) at ../softmmu/physmem.c:2488
#8 0x0000555555b380de in access_with_adjusted_size
(addr=addr@entry=3845, value=value@entry=0x7fffefffdf88,
size=size@entry=1, access_size_min=<optimized out>,
access_size_max=<optimized out>, access_fn=
0x555555b3aa80 <memory_region_write_with_attrs_accessor>,
mr=0x7fff84710bb0, attrs=...) at ../softmmu/memory.c:549
#9 0x0000555555b3c449 in memory_region_dispatch_write
(mr=mr@entry=0x7fff84710bb0, addr=addr@entry=3845, data=<optimized out>,
data@entry=40, op=op@entry=MO_8, attrs=...)
at ../softmmu/memory.c:1511
#10 0x0000555555c07b4c in io_writex
(env=env@entry=0x55555666a820,
iotlbentry=iotlbentry@entry=0x7fff843367f0, mmu_idx=1, val=val@entry=40,
addr=addr@entry=4261416709,
retaddr=retaddr@entry=140736116523268, op=MO_8) at
../accel/tcg/cputlb.c:1420
#11 0x0000555555c0b5df in store_helper (op=MO_8, retaddr=<optimized
out>, oi=<optimized out>, val=40, addr=4261416709, env=0x55555666a820)
at ../accel/tcg/cputlb.c:2355
#12 full_stb_mmu (env=0x55555666a820, addr=4261416709, val=40,
oi=<optimized out>, retaddr=140736116523268) at
../accel/tcg/cputlb.c:2404
#13 0x00007fffae3b8104 in code_gen_buffer ()
#14 0x0000555555bfcfab in cpu_tb_exec (cpu=cpu@entry=0x555556661360,
itb=itb@entry=0x7fffae3b7fc0 <code_gen_buffer+56197011>,
tb_exit=tb_exit@entry=0x7fffefffe668)
at ../accel/tcg/cpu-exec.c:357
#15 0x0000555555bfe089 in cpu_loop_exec_tb (tb_exit=0x7fffefffe668,
last_tb=<synthetic pointer>, tb=0x7fffae3b7fc0
<code_gen_buffer+56197011>, cpu=0x555556661360)
at ../accel/tcg/cpu-exec.c:833
#16 cpu_exec (cpu=cpu@entry=0x555556661360) at ../accel/tcg/cpu-exec.c:992
#17 0x0000555555c1bba0 in tcg_cpus_exec (cpu=cpu@entry=0x555556661360)
at ../accel/tcg/tcg-accel-ops.c:67
#18 0x0000555555c1c3d7 in rr_cpu_thread_fn
(arg=arg@entry=0x555556661360) at ../accel/tcg/tcg-accel-ops-rr.c:214
#19 0x0000555555d5c049 in qemu_thread_start (args=0x7fffefffe750) at
../util/qemu-thread-posix.c:556
#20 0x00007ffff6a95dea in start_thread () at /lib64/libpthread.so.0
#21 0x00007ffff69c8fdf in clone () at /lib64/libc.so.6