CVE-2024-40970

In the Linux kernel, the following vulnerability has been resolved:
Avoid hw_desc array overrun in dw-axi-dmac
I have a use case where nr_buffers = 3 and in which each descriptor is
composed by 3
segments, resulting in the DMA channel descs_allocated to be 9. Since
axi_desc_put()
handles the hw_desc considering the descs_allocated, this scenario would
result in a
kernel panic (hw_desc array will be overrun).
To fix this, the proposal is to add a new member to the axi_dma_desc
structure,
where we keep the number of allocated hw_descs (axi_desc_alloc()) and use
it in
axi_desc_put() to handle the hw_desc array correctly.
Additionally I propose to remove the axi_chan_start_first_queued() call
after completing
the transfer, since it was identified that unbalance can occur (started
descriptors can
be interrupted and transfer ignored due to DMA channel not being enabled).