Techniques for synchronizing use of buffer descriptors for data, such as packets transmitted over a network, include receiving private index data that indicates a particular buffer descriptor owned by a DMA controller, for moving data between a data port and a corresponding memory buffer. A write command is placed on a memory exchange queue to change the owner to a different processor and the private index data is incremented. A public index is determined, which indicates a different buffer descriptor in which the owner is most recently changed to the processor and is known to be visible to the processor. In response to receiving a request from the processor for the most recent buffer descriptor changed to processor ownership, the public index data is sent to the processor. Based on the public index data, the processor exchanges data with buffer descriptors guaranteed to be owned by the processor.