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Peter Xu
67eae54bc2
We used to have a report that pte-marker code can be reached even when uffd-wp is not compiled in for file memories, here: https://lore.kernel.org/all/YzeR+R6b4bwBlBHh@x1n/T/#u I just got time to revisit this and found that the root cause is we simply messed up with the vma check, so that for !PTE_MARKER_UFFD_WP system, we will allow UFFDIO_REGISTER of MINOR & WP upon shmem as the check was wrong: if (vm_flags & VM_UFFD_MINOR) return is_vm_hugetlb_page(vma) || vma_is_shmem(vma); Where we'll allow anything to pass on shmem as long as minor mode is requested. Axel did it right when introducing minor mode but I messed it up inb1f9e87686when moving code around. Fix it. Link: https://lkml.kernel.org/r/20221024193336.1233616-1-peterx@redhat.com Link: https://lkml.kernel.org/r/20221024193336.1233616-2-peterx@redhat.com Fixes:b1f9e87686("mm/uffd: enable write protection for shmem & hugetlbfs") Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.