Messages in this thread |  | | Date | Sun, 24 Apr 2022 18:03:32 +0800 | Subject | Re: [PATCH] mm: hugetlb: Add missing cache flushing in hugetlb_unshare_all_pmds() | From | Baolin Wang <> |
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On 4/24/2022 3:45 PM, Muchun Song wrote: > On Sun, Apr 24, 2022 at 02:33:19PM +0800, Baolin Wang wrote: >> 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. >> >> Fixes: 6dfeaff93be1 ("hugetlb/userfaultfd: unshare all pmds for hugetlbfs when register wp") >> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> > > CONFIG_ARCH_WANT_HUGE_PMD_SHARE is only definded on riscv, arm64 and > x86. All of them do not have a VIVT cache. In others words, > flush_cache_range() is null on those architectures. So I suspect > in practice this does not cause any issue. It is better to > clarify this in commit log.
Yes, just from code inspection and to keep same behaviors when unmapping sharing PMD entrires in case more architectures can support CONFIG_ARCH_WANT_HUGE_PMD_SHARE in future. Will update the commit message in next version.
> > Anyway: > > Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Thanks.
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