Messages in this thread | | | Date | Thu, 2 Mar 2023 17:57:34 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH v1] mm/userfaultfd: propagate uffd-wp bit when PTE-mapping the huge zeropage |
| |
On Thu, 2 Mar 2023 18:54:23 +0100 David Hildenbrand <david@redhat.com> wrote:
> Currently, we'd lose the userfaultfd-wp marker when PTE-mapping a huge > zeropage, resulting in the next write faults in the PMD range > not triggering uffd-wp events. > > Various actions (partial MADV_DONTNEED, partial mremap, partial munmap, > partial mprotect) could trigger this. However, most importantly, > un-protecting a single sub-page from the userfaultfd-wp handler when > processing a uffd-wp event will PTE-map the shared huge zeropage and > lose the uffd-wp bit for the remainder of the PMD. > > Let's properly propagate the uffd-wp bit to the PMDs. > > ... > > Fixes: e06f1e1dd499 ("userfaultfd: wp: enabled write protection in userfaultfd API") > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> > Cc: Andrea Arcangeli <aarcange@redhat.com> > Cc: Peter Xu <peterx@redhat.com> > Cc: Jerome Glisse <jglisse@redhat.com> > Cc: Shaohua Li <shli@fb.com> > Signed-off-by: David Hildenbrand <david@redhat.com>
Do you agree that a -stable backport is appropriate?
| |