I'm confused by this code, 'bmc' is created as:
bmc = g_new0(AspeedBoardState, 1);
Then we use it as QOM owner for different MemoryRegion objects.
But looking at memory_region_init_ram (similarly for ROM):
void memory_region_init_ram(MemoryRegion *mr,
struct Object *owner,
const char *name,
uint64_t size,
Error **errp)
{
DeviceState *owner_dev;
Error *err = NULL;
memory_region_init_ram_nomigrate(mr, owner, name, size, &err);
if (err) {
error_propagate(errp, err);
return;
}
/* This will assert if owner is neither NULL nor a DeviceState.
* We only want the owner here for the purposes of defining a
* unique name for migration. TODO: Ideally we should implement
* a naming scheme for Objects which are not DeviceStates, in
* which case we can relax this restriction.
*/
owner_dev = DEVICE(owner);
vmstate_register_ram(mr, owner_dev);
}
The expected assertion is not triggered ('bmc' is not NULL neither
a DeviceState).
'bmc' structure is defined as:
struct AspeedBoardState {
AspeedSoCState soc;
MemoryRegion ram_container;
MemoryRegion max_ram;
};
What happens is when using 'OBJECT(bmc)', the QOM macros cast the
memory pointed by bmc, which first member is 'soc', which is
initialized ...:
object_initialize_child(OBJECT(machine), "soc",
&bmc->soc, amc->soc_name);
The 'soc' object is indeed a DeviceState, so the assertion passes.
Since this is fragile and only happens to work by luck, remove the
dangerous OBJECT(bmc) owner argument.
Note, this probably breaks migration for this machine.
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20200623072132.2868-2-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
f489960d36