Children are automatically unparented so manually unparenting is unnecessary.
Worse, automatic unparenting happens before the insntance_finalize() callback of the parent gets called, so object_unparent() calls in the callback will refer to objects that are already unparented, which is semantically incorrect. Remove the instruction to call object_unparent(), and the exception of the "do not call object_unparent()" rule for instance_finalize. Signed-off-by: Akihiko Odaki <od...@rsg.ci.i.u-tokyo.ac.jp> --- docs/devel/memory.rst | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) diff --git a/docs/devel/memory.rst b/docs/devel/memory.rst index 57fb2aec76e066236d33efe1033d2e73c7f7c295..749f11d8a4ddc80f2d44b66fa41fb12c0fa54006 100644 --- a/docs/devel/memory.rst +++ b/docs/devel/memory.rst @@ -161,18 +161,11 @@ or never. Destruction of a memory region happens automatically when the owner object dies. -If however the memory region is part of a dynamically allocated data -structure, you should call object_unparent() to destroy the memory region -before the data structure is freed. For an example see VFIOMSIXInfo -and VFIOQuirk in hw/vfio/pci.c. - You must not destroy a memory region as long as it may be in use by a device or CPU. In order to do this, as a general rule do not create or -destroy memory regions dynamically during a device's lifetime, and only -call object_unparent() in the memory region owner's instance_finalize -callback. The dynamically allocated data structure that contains the -memory region then should obviously be freed in the instance_finalize -callback as well. +destroy memory regions dynamically during a device's lifetime. +The dynamically allocated data structure that contains the +memory region should be freed in the instance_finalize callback. If you break this rule, the following situation can happen: @@ -198,9 +191,9 @@ this exception is rarely necessary, and therefore it is discouraged, but nevertheless it is used in a few places. For regions that "have no owner" (NULL is passed at creation time), the -machine object is actually used as the owner. Since instance_finalize is -never called for the machine object, you must never call object_unparent -on regions that have no owner, unless they are aliases or containers. +machine object is actually used as the owner. You must never call +object_unparent on regions that have no owner, unless they are aliases +or containers. Overlapping regions and priority -- 2.51.0
