[PATCH 0/5] x86/mm/pat: CPA fixes

There are a couple of CPA fixes floating around:

Denis Lunev fixed races between split and collapse of the large mappings:

https://lore.kernel.org/all/[email protected]

Lorenzo Stoakes fixed UAF caused by races between CPA and ptdump:

https://lore.kernel.org/all/[email protected]

and an issue with stale page tables in IOMMU:

https://lore.kernel.org/all/[email protected]

Mike Rapoport fixed a check of RW attribute in lookup_address_in_pgd_attr()
used for the verification of RWX:

https://lore.kernel.org/all/[email protected]

Some of the fixes got merged into x86 tree, some of them got merged into mm
tree and some are still hanging in the air.

Beside the fixes there was a supposed simplification of cpa_lock locking 
that looked like removal of an optimization for DEBUG_PAGEALLOC, but it
turned out that it was not an optimization but rather a correctness
guard because with DEBUG_PAGEALLOC the locks could be taken in an atomic
context and couldn't use plain spin_lock()/spin_unlock().

The changes here are collected from all these fixes into a sinlge coherent
set on top of tip/x86/mm:
 
* update to cpa_lock handling with DEBUG_PAGEALLOC
* fix for races between CPA and ptdumpi causing UAF
* fix for stale page tables in IOMMU
* update to the fix of the race between split and collapse of large
  mappings
* fix for effective RW computation in lookup_address_in_pgd_attr()

Signed-off-by: Mike Rapoport (Microsoft) <[email protected]>
---
Lorenzo Stoakes (ARM) (3):
      x86/mm/pat: acquire init_mm write lock on collapse to avoid UAF
      x86/mm/pat: acquire init_mm read lock on attribute change to avoid UAF
      x86/mm/pat: allocate split page tables as kernel page tables

Mike Rapoport (Microsoft) (2):
      x86/mm/pat: introcude cpa_lock() and cpa_unlock()
      x86/mm/pat: fix effective RW computation in lookup_address_in_pgd_attr()

 arch/x86/mm/pat/set_memory.c | 95 +++++++++++++++++++++++++++++++-------------
 include/linux/mmap_lock.h    |  2 +
 2 files changed, 70 insertions(+), 27 deletions(-)
---
base-commit: a5a162fe1ae130e3d2ceefef3f43afe3773c1d56
change-id: 20260727-cpa-fixes-d3c73c075672

--
Sincerely yours,
Mike.