mm: hugetlb: add missing cache flushing in hugetlb_unshare_all_pmds()

Missed calling flush_cache_range() before removing the sharing PMD
entrires, otherwise data consistence issue may be occurred on some
architectures whose caches are strict and require a virtual>physical
translation to exist for a virtual address.  Thus add it.

Now no architectures enabling PMD sharing will be affected, since they do
not have a VIVT cache.  That means this issue can not be happened in
practice so far.

Link: https://lkml.kernel.org/r/47441086affcabb6ecbe403173e9283b0d904b38.1650956489.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/419b0e777c9e6d1454dcd906e0f5b752a736d335.1650781755.git.baolin.wang@linux.alibaba.com
Fixes: 6dfeaff93b ("hugetlb/userfaultfd: unshare all pmds for hugetlbfs when register wp")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

This commit is contained in:

Baolin Wang

2022-04-29 14:36:58 -07:00

committed by

akpm

parent 25fa414ada

commit 9c8bbfaca1

1 changed files with 1 additions and 0 deletions

									
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mm/hugetlb.c

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				@ -6886,6 +6886,7 @@ void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)

					if (start >= end)

						return;

					flush_cache_range(vma, start, end);

					/*

					 * No need to call adjust_range_if_pmd_sharing_possible(), because

					 * we have already done the PUD_SIZE alignment.

mm: hugetlb: add missing cache flushing in hugetlb_unshare_all_pmds()

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mm/hugetlb.c

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