In the Linux kernel, the following vulnerability has been resolved:
iio: buffer: Tie IIO dma fence lock lifetime to the fence
The `iio_dma_fence` implementation currently uses a lock embedded in the
`iio_dmabuf_priv`. But the `iio_dma_fence` can outlive the
`iio_dmabuf_priv`, which can cause a use-after-free.
Tie the lifetime of the lock to the lifetime of the fence by embedding them
in the same struct.
We can’t just hold a reference to the `iio_dmabuf_priv` from the
`iio_dma_fence` since `iio_buffer_dmabuf_release()` might sleep and the
fence release callback is not allowed to sleep.
Note that the `dma_fence` framework now has an internal lock that gets used
when the passing `NULL` for `lock` in `dma_fence_init()`, but in order to
allow this patch to be backportable use an external lock.
