Re: [PATCH v5 31/38] mm/uffd: use predicates for userfaultfd checks
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From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Date: 2026-10-13 11:29:49
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On Mon, Oct 12, 2026 at 08:48:04PM +0200, David Hildenbrand (Arm) wrote:
On 10/9/26 20:04, Lorenzo Stoakes (ARM) wrote:
quoted
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 949017e60608..f33b04700838 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c
quoted
@@ -2146,10 +2152,11 @@ static bool vma_can_userfault(struct vm_area_struct *vma, vm_flags_t vm_flags, { const struct vm_uffd_ops *ops = vma_uffd_ops(vma); - if (vma->vm_flags & (VM_DROPPABLE | VM_SHADOW_STACK)) + /* Only mm-backed memory can have its faults handled by userspace. */ + if (!vma_is_mm_backed(vma)) return false;Again, for both I would prefer keeping the droppable check separate.
Ack as per discussion on other thread, will separate out for v6!
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Thanks! -- Cheers, Lorenzo