On 28.10.22 03:32, Hugh Dickins wrote:
Reinstating Cc stable, which I removed just before the discussion settled.
Sorry for not reading the full thread before and considering Peters
mail; I had to take short cuts :)
On Thu, 27 Oct 2022, Peter Xu wrote:
...
After a re-read and 2nd thought, I think David has a valid point in that we
shouldn't have special handling of !anon pages on CoW during fork(),
because that seems to be against the fundamental concept of fork().
So now I think I agree the !Anon original check does look a bit cleaner,
and also make fork() behavior matching with the old/new kernels, irrelevant
of the pin mess.
Thanks Peter. So Yuanzheng's patch for 5.10 is exactly right.
Sorry for leading everyone astray: my mistake was to suppose that
its !PageAnon check was simply to avoid the later BUG_ON(!anon_vma):
whereas David and Peter now agree that it actually corrects the
semantics for fork() on file pages.
I lift my hold on Yuanzheng's patch: nobody actually said "Acked-by",
but I think the discussion and resolution have given better than that.
(No 3rd thoughts please!)
Unless someone tells me why I am obviously wrong
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David / dhildenb
