Jann Horn 3ffb97fce2 mm: Force TLB flush for PFNMAP mappings before unlink_file_vma()
commit b67fbebd4cf980aecbcc750e1462128bffe8ae15 upstream.

Some drivers rely on having all VMAs through which a PFN might be
accessible listed in the rmap for correctness.
However, on X86, it was possible for a VMA with stale TLB entries
to not be listed in the rmap.

This was fixed in mainline with
commit b67fbebd4cf9 ("mmu_gather: Force tlb-flush VM_PFNMAP vmas"),
but that commit relies on preceding refactoring in
commit 18ba064e42df3 ("mmu_gather: Let there be one tlb_{start,end}_vma()
implementation") and commit 1e9fdf21a4339 ("mmu_gather: Remove per arch
tlb_{start,end}_vma()").

This patch provides equivalent protection without needing that
refactoring, by forcing a TLB flush between removing PTEs in
unmap_vmas() and the call to unlink_file_vma() in free_pgtables().

[This is a stable-specific rewrite of the upstream commit!]
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-05 10:30:03 +02:00
..
2021-05-07 00:26:35 -07:00
2021-05-05 11:27:24 -07:00
2021-05-05 11:27:24 -07:00
2021-06-29 10:53:52 -07:00
2021-09-13 10:18:28 -07:00
2021-06-05 20:43:15 +00:00
2021-05-07 00:26:35 -07:00
2021-04-16 16:10:37 -07:00
2021-05-07 00:26:35 -07:00