Description: hugetlbfs: flush TLBs correctly after huge_pmd_unshare
References:
 https://www.openwall.com/lists/oss-security/2021/11/25/1
Notes:
 carnil> For 5.16-rc1 onwards only additionally there is 13e4ad2ce8df
 carnil> ("hugetlbfs: flush before unlock on
 carnil> move_hugetlb_page_tables()") to be applied.
Bugs:
upstream: released (5.16-rc3) [a4a118f2eead1d6c49e00765de89878288d4b890]
5.10-upstream-stable: released (5.10.82) [40bc831ab5f630431010d1ff867390b07418a7ee]
4.19-upstream-stable: released (4.19.219) [b0313bc7f5fbb6beee327af39d818ffdc921821a]
4.9-upstream-stable: released (4.9.292) [8e80bf5d001594b037de04fb4fe89f34cfbcb3ba]
sid: released (5.15.5-1)
5.10-bullseye-security: released (5.10.84-1)
4.19-buster-security: released (4.19.232-1)
4.9-stretch-security: released (4.9.303-1)