[Linaro-mm-sig] Re: [PATCH] dma-buf: Require VM_PFNMAP vma for mmap

[Jason Gunthorpe]

On Wed, Nov 23, 2022 at 04:15:05PM +0100, Christian König wrote:

> I have not the slightest idea how people got this impression, but I have
> heard it so many time from so many different sources that there must be some
> common cause to this. Is the maybe some book or tutorial how to sophisticate
> break the kernel or something like this?
> 
> Anyway as far as I can see only correct approach would be to use an MMU
> notifier or more high level hmm_range_fault()+seq number.

It already uses a mmu notifier, this is why I have no idea what the
page ref is doing..

Jason