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linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, fuse-devel@lists.linux.dev, Ihor Solodrai , Bert Karwatzki Subject: Re: [PATCH v5 31/38] mm/uffd: use predicates for userfaultfd checks Message-ID: References: <20261009-b4-mmap-prepare-vma-flag-sanify-v5-0-923b70125b1e@kernel.org> <20261009-b4-mmap-prepare-vma-flag-sanify-v5-31-923b70125b1e@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 223978000C X-Rspam-User: X-Stat-Signature: zqisnk7jgbfch7pbz87e66jeynmm5y5c X-HE-Tag: 1791890989-619934 X-HE-Meta: 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 YaYU16O2 AihKvGAXMgv5UbiX6FCGO9r54s6k27ul7fC6dA9RXtHOUTw5YtjMcbNuFsBGRFc6Jf3LSEWzROVErTzBlYLE+R3LQDRQ07f1dmMNZMJt1e0lzYHw6j0xc4DsPkjdT5wpp7ZneQsPuaUFbyexv8hEufa8LdJHPK/rMjy3o4w3uXqn8ZLY/ZFIqFNHHJcKXE+vB4aF1Gs+TQMOK0F1Mu3TzT2E4KbTmHpNXRgosukuqZdImtXr7RgWnqtCreWt7VqGH3ptu3f66yCyNrmpJj/kdd9e2ypvCFU+O34VgwVEmx0cspJOBI8vQVbADaoi6ZqMg= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Oct 12, 2026 at 08:48:04PM +0200, David Hildenbrand (Arm) wrote: > On 10/9/26 20:04, Lorenzo Stoakes (ARM) wrote: > > diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c > > index 949017e60608..f33b04700838 100644 > > --- a/mm/userfaultfd.c > > +++ b/mm/userfaultfd.c > > @@ -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) Thanks! -- Cheers, Lorenzo