[PATCH 6.6.y 0/5] fix error handling in mmap_region() and refactor (hotfixes)

[Lorenzo Stoakes]

Critical fixes for mmap_region(), backported to 6.6.y.

Some notes on differences from upstream:

* In this kernel is_shared_maywrite() does not exist and the code uses
  VM_SHARED to determine whether mapping_map_writable() /
  mapping_unmap_writable() should be invoked. This backport therefore
  follows suit.

* Each version of these series is confronted by a slightly different
  mmap_region(), so we must adapt the change for each stable version. The
  approach remains the same throughout, however, and we correctly avoid
  closing the VMA part way through any __mmap_region() operation.

Lorenzo Stoakes (5):
  mm: avoid unsafe VMA hook invocation when error arises on mmap hook
  mm: unconditionally close VMAs on error
  mm: refactor map_deny_write_exec()
  mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling
  mm: resolve faulty mmap_region() error path behaviour

 arch/arm64/include/asm/mman.h  |  10 ++-
 arch/parisc/include/asm/mman.h |   5 +-
 include/linux/mman.h           |  28 ++++++--
 mm/internal.h                  |  45 ++++++++++++
 mm/mmap.c                      | 128 ++++++++++++++++++---------------
 mm/mprotect.c                  |   2 +-
 mm/nommu.c                     |   9 ++-
 mm/shmem.c                     |   3 -
 8 files changed, 153 insertions(+), 77 deletions(-)

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2.47.0