On 12/22/22 21:55, David Hildenbrand wrote: > We have to update the uffd-wp SWP PTE bit independent of the type of > migration entry. Currently, if we're unlucky and we want to install/clear > the uffd-wp bit just while we're migrating a read-only mapped hugetlb page, > we would miss to set/clear the uffd-wp bit. > > Further, if we're processing a readable-exclusive > migration entry and neither want to set or clear the uffd-wp bit, we > could currently end up losing the uffd-wp bit. Note that the same would > hold for writable migrating entries, however, having a writable > migration entry with the uffd-wp bit set would already mean that > something went wrong. > > Note that the change from !is_readable_migration_entry -> > writable_migration_entry is harmless and actually cleaner, as raised by > Miaohe Lin and discussed in [1]. > > [1] https://lkml.kernel.org/r/90dd6a93-4500-e0de-2bf0-bf522c311b0c@xxxxxxxxxx > > Fixes: 60dfaad65aa9 ("mm/hugetlb: allow uffd wr-protect none ptes") > Cc: <stable@xxxxxxxxxxxxxxx> > Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> > --- > mm/hugetlb.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) Thanks, Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> -- Mike Kravetz
