mm: Force TLB flush for PFNMAP mappings before unlink_file_vma()
commit b67fbebd 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 b67fbebd ("mmu_gather: Force tlb-flush VM_PFNMAP vmas"), but that commit relies on preceding refactoring in commit 18ba064e ("mmu_gather: Let there be one tlb_{start,end}_vma() implementation") and commit 1e9fdf21 ("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>
parent
18ed766f
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