Re: [PATCH-for-6.2] qom/object: Ignore global properties with empty name

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 19 Nov 2021 12:32:29 +0100
Philippe Mathieu-Daudé <philmd@redhat.com> wrote:

> When using -global, properties might have empty name/value.
> 
> This fixes this legitimate use case:
> 
>   $ qemu-system-x86_64 -global driver=isa-fdc
>   qemu-system-x86_64: ../../devel/qemu/qapi/string-input-visitor.c:394:
>   string_input_visitor_new: Assertion `str' failed.
>   Aborted (core dumped)

why ignore instead of printing error message and exiting?
it never worked before, and I don't see a reason to let QEMU startup fine
with nonsense CLI.

> 
>   (gdb) bt
>   #4  0x0000555555f6b8d5 in string_input_visitor_new (str=0x0) at qapi/string-input-visitor.c:394
>   #5  0x0000555555dd0f8d in object_property_parse (obj=0x555556f33400, name=0x0, string=0x0, errp=0x7fffffffc9c8) at qom/object.c:1641
>   #6  0x0000555555dce131 in object_apply_global_props (obj=0x555556f33400, props=0x555556737360, errp=0x555556611760 <error_fatal>) at qom/object.c:411
>   #7  0x0000555555dc5ee2 in qdev_prop_set_globals (dev=0x555556f33400) at hw/core/qdev-properties.c:790
>   #8  0x0000555555dc89e8 in device_post_init (obj=0x555556f33400) at hw/core/qdev.c:697
>   #9  0x0000555555dce02b in object_post_init_with_type (obj=0x555556f33400, ti=0x55555672bd20) at qom/object.c:383
>   #10 0x0000555555dce059 in object_post_init_with_type (obj=0x555556f33400, ti=0x5555566e9090) at qom/object.c:387
>   #11 0x0000555555dce059 in object_post_init_with_type (obj=0x555556f33400, ti=0x5555566df730) at qom/object.c:387
>   #12 0x0000555555dce566 in object_initialize_with_type (obj=0x555556f33400, size=848, type=0x5555566df730) at qom/object.c:519
>   #13 0x0000555555dcec78 in object_new_with_type (type=0x5555566df730) at qom/object.c:733
>   #14 0x0000555555dceccf in object_new (typename=0x5555560fcf81 "isa-fdc") at qom/object.c:748
>   #15 0x0000555555dc75fe in qdev_new (name=0x5555560fcf81 "isa-fdc") at hw/core/qdev.c:153
>   #16 0x00005555559eec58 in isa_new (name=0x5555560fcf81 "isa-fdc") at hw/isa/isa-bus.c:166
>   #17 0x0000555555bd3607 in pc_superio_init (isa_bus=0x5555566b42e0, create_fdctrl=true, no_vmport=false) at hw/i386/pc.c:1026
>   (gdb) fr 6
>   #6  0x0000555555dce131 in object_apply_global_props (obj=0x555556f33400, props=0x555556737360, errp=0x555556611760 <error_fatal>) at qom/object.c:411
>   411             if (!object_property_parse(obj, p->property, p->value, &err)) {
>   (gdb) p *p
>   $1 = {driver = 0x555556738250 "isa-fdc", property = 0x0, value = 0x0, used = true, optional = false}
> 
> Reported-by: Thomas Huth <thuth@redhat.com>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/604
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  qom/object.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/qom/object.c b/qom/object.c
> index 4f0677cca9e..45fa8561df6 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -401,6 +401,9 @@ bool object_apply_global_props(Object *obj, const GPtrArray *props,
>          GlobalProperty *p = g_ptr_array_index(props, i);
>          Error *err = NULL;
>  
> +        if (!p->property) {
> +            continue;
> +        }
>          if (object_dynamic_cast(obj, p->driver) == NULL) {
>              continue;
>          }