Hugh reported issue with F_SEAL_FUTURE_WRITE not applied correctly to hugetlbfs, which I can easily verify using the memfd_test program, which seems that the program is hardly run with hugetlbfs pages (as by default shmem). Meanwhile I found another probably even more severe issue on that hugetlb fork won't wr-protect child cow pages, so child can potentially write to parent private pages. Patch 2 addresses that. After this series applied, "memfd_test hugetlbfs" should start to pass. Please review, thanks. Peter Xu (2): mm/hugetlb: Fix F_SEAL_FUTURE_WRITE mm/hugetlb: Fix cow where page writtable in child fs/hugetlbfs/inode.c | 5 +++++ include/linux/mm.h | 32 ++++++++++++++++++++++++++++++++ mm/hugetlb.c | 2 ++ mm/shmem.c | 22 ++++------------------ 4 files changed, 43 insertions(+), 18 deletions(-) -- 2.31.1
