mbox series

[v1,0/2] mm/hugetlb: fix write-fault handling for shared mappings

Message ID 20220805110329.80540-1-david@redhat.com (mailing list archive)
Headers show
Series mm/hugetlb: fix write-fault handling for shared mappings | expand

Message

David Hildenbrand Aug. 5, 2022, 11:03 a.m. UTC 
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 one case where we could currently get such faults and would
erroneously map an anon page into a shared mapping, by triggering
clear_refs to clear soft-dirty tracking at the wrong point in time on a
process.

I propose to backport the fix to stable trees, as the fix for write-notify
should be straight forward.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

David Hildenbrand (2):
  mm/hugetlb: fix hugetlb not supporting write-notify
  mm/hugetlb: support write-faults in shared mappings

 mm/hugetlb.c | 21 ++++++++++++++-------
 mm/mmap.c    |  7 +++++++
 2 files changed, 21 insertions(+), 7 deletions(-)