Update on CPA fixes, x86/urgent and x86/mm

[Dave Hansen]

OK, so Linus pulled the x86/urgent fixes I sent earlier today. I've
staged everything else. Here's an explanation for where that leaves the
other x86 fixes.

==== x86/urgent ====

x86/urgent has 5 urgent fixes in it. There are 4 that are CPA-related.
These fix some use-after-free issues that have been blocking mm folks
from making forward progress on some other features they're working on.
So they're impacting real people. They're not new bugs, but they're
annoying enough not to want to wait until the merge window:

      x86/mm/pat: Acquire init_mm write lock on collapse to avoid UAF
      x86/mm/pat: Acquire init_mm read lock on attribute changes...
      x86/mm/pat: Allocate split page tables as kernel page tables
      x86/alternatives: Exclude text poking against change_page_attr()

The other one is old as well, but it's actually causing user data loss.
It's a relatively obscure set of features and requires heavy reclaim to
trigger, which explains why it wasn't found for so long. But the side
effects are rather nasty, so it needs fixing upstream now.

      x86/mm: Fix user-space data loss with MADV_FREE and THP

====== x86/mm ======

x86/mm now has a single commit:

      x86/mm/pat: Fix effective RW computation in ...

But, being a bug fix for a bug detector, folks have bisected a
"regression" to it:

	https://lore.kernel.org/all/20260905044253.GA3816371@ax162/

It is a great and very welcome bug report, but appears to be a
false-positive. Rather than deal with a pile of these in Linus's tree,
keeping this in x86/mm and getting it linux-next exposure for the coming
weeks seems prudent.

I hope this makes sense to everyone.