[question] qemu abort when object-add is called with an already used id

[Auger Eric]

Hi,

While testing PCDIMM hotplug/coldplug I noted qemu aborts if we attempt
to add from the QMP monitor an object whose id is already in use.

for instance
object-add qom-type=memory-backend-ram id=mem1 props.size=4294967296
while mem1 is already used.

We get:
Unexpected error in object_property_try_add() at qom/object.c:1167:
attempt to add duplicate property 'mem1' to object (type 'container')

This is due to the fact &error_abort is passed to object_property_try_add().

Is it the expected behavior?

Thanks

Eric


Thread 1 "qemu-system-x86" received signal SIGABRT, Aborted.
[Switching to Thread 0x7ffff7fd0e80 (LWP 411617)]
0x00007ffff5a1370f in raise () from /lib64/libc.so.6
(gdb) where
#0  0x00007ffff5a1370f in raise () at /lib64/libc.so.6
#1  0x00007ffff59fdb25 in abort () at /lib64/libc.so.6
#2  0x000055555581e0dc in error_handle_fatal (errp=<optimized out>,
err=0x555556bc40b0) at util/error.c:40
#3  0x0000555555c572ad in error_setv
    (errp=0x555556557b18 <error_abort>, src=0x555555e34ff3
"qom/object.c", line=1167, func=0x555555e35720 <__func__.18519>
"object_property_try_add", err_class=ERROR_CLASS_GENERIC_ERROR,
fmt=<optimized out>, ap=0x7fffffffd7a0, suffix=0x0) at util/error.c:73
#4  0x0000555555c57430 in error_setg_internal
    (errp=errp@entry=0x555556557b18 <error_abort>,
src=src@entry=0x555555e34ff3 "qom/object.c", line=line@entry=1167,
func=func@entry=0x555555e35720 <__func__.18519>
"object_property_try_add", fmt=fmt@entry=0x555555e35438 "attempt to add
duplicate property '%s' to object (type '%s')") at util/error.c:97
#5  0x0000555555b5bf48 in object_property_try_add
    (obj=obj@entry=0x5555567ef280, name=name@entry=0x7ffee4003f80
"mem1", type=type@entry=0x5555573c0dc0 "child<memory-backend-ram>",
get=get@entry=0x555555b5d6b0 <object_get_child_property>,
set=set@entry=0x0, release=release@entry=0x555555b5b930
<object_finalize_child_property>, opaque=0x5555569158a0,
errp=0x555556557b18 <error_abort>) at qom/object.c:1166
#6  0x0000555555b5cf5c in object_property_add
    (opaque=0x5555569158a0, release=0x555555b5b930
<object_finalize_child_property>, set=0x0, get=0x555555b5d6b0
<object_get_child_property>, type=0x5555573c0dc0
"child<memory-backend-ram>", name=0x7ffee4003f80 "mem1",
obj=0x5555567ef280) at qom/object.c:1664
#7  0x0000555555b5cf5c in object_property_add_child (obj=0x5555567ef280,
name=name@entry=0x7ffee4003f80 "mem1", child=child@entry=0x5555569158a0)
at qom/object.c:1664
#8  0x0000555555b5e961 in user_creatable_add_type
    (type=type@entry=0x7ffee4004410 "memory-backend-ram",
id=id@entry=0x7ffee4003f80 "mem1", qdict=qdict@entry=0x7ffee40061d0,
v=v@entry=
    0x55555763d3e0, errp=errp@entry=0x7fffffffd9d8) at
qom/object_interfaces.c:85
#9  0x0000555555b5eb66 in user_creatable_add_dict (qdict=0x7ffee40061d0,
keyval=<optimized out>, errp=0x7fffffffd9d8) at qom/object_interfaces.c:131
#10 0x0000555555c06b70 in qmp_dispatch (cmds=0x555556555620
<qmp_commands>, request=<optimized out>, allow_oob=<optimized out>) at
qapi/qmp-dispatch.c:155
#11 0x0000555555b06d01 in monitor_qmp_dispatch (mon=0x555556823800,
req=<optimized out>) at monitor/qmp.c:145
#12 0x0000555555b0751a in monitor_qmp_bh_dispatcher (data=<optimized
out>) at monitor/qmp.c:234
#13 0x0000555555c622c5 in aio_bh_call (bh=0x5555565da750) at
util/async.c:164
#14 0x0000555555c622c5 in aio_bh_poll (ctx=ctx@entry=0x5555565d92c0) at
util/async.c:164
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