Re: [PATCH 03/14] mm/hmm: HMM should have a callback before MM is destroyed v2

[Andrew Morton]

On Fri, 16 Mar 2018 15:14:08 -0400 jglisse@xxxxxxxxxx wrote:

> The hmm_mirror_register() function registers a callback for when
> the CPU pagetable is modified. Normally, the device driver will
> call hmm_mirror_unregister() when the process using the device is
> finished. However, if the process exits uncleanly, the struct_mm
> can be destroyed with no warning to the device driver.

Again, what are the user-visible effects of the bug?  Such info is
needed when others review our request for a -stable backport.  And the
many people who review -stable patches for integration into their own
kernel trees will want to understand the benefit of the patch to their
users.