Re: [PATCH 1/2] mm/memfd_luo: reject memfds whose page count exceeds UINT_MAX

[David CARLIER]

On 2026-05-01 18:59, Pasha Tatashin wrote:
  > I think, the fix should be first done at memfd_pin_folios() to
change
  > max_folios to 'long' or 'unsigned long', and then just updated
  > memfd_luo.c to match.

  Even with memfd_pin_folios() widened, memfd_luo_preserve_folios()
still
  kvmalloc_objs()s the folios array up front -- at UINT_MAX entries
that's
  already ~32 GiB of pointer array, which won't realistically succeed.
So
  the guard here still makes sense, just on allocation grounds rather than
  interface truncation.

  Happy to widen memfd_pin_folios() as a separate patch, but I'd keep
the
  -EFBIG check regardless. Or did you have a different shape in mind?

Cheers.