Hi： I have two questions about cteDelete of sel4 kernel？ IF I want to delete slot that slot->cap is cnode object(I called it level 1 cnode). The finaliseSlot function will create zombie capability and call reduceZombie(), param "immediate" is ture. the reduceZombie() call cteDelete() delete the endSlot, if the endSlot->cap is cnode capability again(I call it level 2 cnode), this time param "immediate" is false. and cteDelete() will call reduceZombie again, but because param "immediate " is false ,this time reduceZombie will not call cteDelete recursively. the reduceZombie will call capSwapForDelete，it will swap zombie cap with slot 0 of level 2 cnode, if Swap cap(slot0 of level 2 cnode) is not cnode or tcb(the cnode object slot 0 must point to cnode self ? I did not find this limitation), when it return to finaliseSlot, finaliseSlot will check finaliseCap, because swap cap is not cnode or tcb, almost it call be capRemovable, and it return directly. 1. I think when call capSwapForDelete in reduceZombie, the level 2 cnode become Cyclic zombie, but when return finaliseSlot, I do not think it will deal with below branch: if (!immediate && capCyclicZombie(fc_ret.remainder, slot)) { } because this time ,slot ->cap is not cnode or tcb, it will not create zombie cap. then Who will delete level 2 cnode ? Is it lost as "Cyclic zombie", memory leak? 2. when delete cnode, it will check "preemptionPoint", if our delete is beak, even though fs_ret.success is false, but this false is not deliver to caller who will delete it again? thank you for your help