Re: [Qemu-devel] [PATCH v4 4/6] vhost: add regions to temporary list

[Paolo Bonzini]

On 15/12/2017 14:30, Dr. David Alan Gilbert wrote:
>> Also it seems that we have a race in current code where
>> region_del() unrefs memory region first and then by the
>> commit time memory region could be gone since old flatview
>> is unreffed before commit callback is called, but guest still
>> uses old memory map until vhost_set_mem_table() is complete.
>> We probably should unref deleted(old) sections after
>> guest gets new memmap.
>
> Will they really get cleaned up before the commit() returns?
> There's no rcu like thing guarding it?

The memory subsystem only keeps them alive until before commmit() is
invoked.

Paolo