I observed that hugetlb does not support/expect write-faults in shared mappings that would have to map the R/O-mapped page writable -- and I found two case where we could currently get such faults and would erroneously map an anon page into a shared mapping. Reproducers part of the patches. I propose to backport both fixes to stable trees. The first fix needs a small adjustment. v1 -> v2: - "mm/hugetlb: fix hugetlb not supporting softdirty tracking" -> Restrict to softdirty tracking - "mm/hugetlb: support write-faults in shared mappings" -> Add reproducer and adjust description -> Move VM_WRITE sanity check out from MAYSHARE handling David Hildenbrand (2): mm/hugetlb: fix hugetlb not supporting softdirty tracking mm/hugetlb: support write-faults in shared mappings mm/hugetlb.c | 26 +++++++++++++++++++------- mm/mmap.c | 7 +++++-- 2 files changed, 24 insertions(+), 9 deletions(-) base-commit: ffcf9c5700e49c0aee42dcba9a12ba21338e8136 -- 2.35.3
