Release DMA Memory

[Matt Davis]

I have a kernel module that communicates to a PCI device via DMA.  The
module allocates the shared memory using dma_alloc_coherent().  When
the module is unloaded, a call to dma_free_coherent() is executed.

My question is, since the DMA memory is not explicitly zeroed before
deallocation, is there a chance that the PCI device could still read
(non-zeroed data) and act upon the DMA memory after the module unloads
and calls dma_free_coherent()?

Thanks!

-Matt