Comment # 25 on bug 73528 from Marek Olšák

My explanations for this bug are:

1) CMASK allocation is wrong. We should try and overallocate it.

2) CMASK contains garbage, which can hang the hardware. Either the clear_buffer
function isn't reliable (it uses CP DMA) or CMASK was corrupted by eviction. Or
an out-of-bounds access from some other source corrupted it.