In the Linux kernel, the following vulnerability has been resolved: iio: buffer: Make IIO DMA...

In the Linux kernel, the following vulnerability has been resolved:

iio: buffer: Make IIO DMA fence release RCU-safe

The dma_fence documentation states that if a custom release implementation is provided, the dma_fence object must be freed in an RCU-safe way. The current iio_dma_fence implementation uses kfree(), which might result in a use-after-free.

Remove the custom release implementation. This makes the DMA fence core fall back to dma_fence_free(), which calls kfree_rcu() on the fence. This requires that the fence be the first member of struct iio_dma_fence.

Using the default release method for extended DMA fence structures is a common pattern.