diff options
| author | Mike Rapoport (Microsoft) <rppt@kernel.org> | 2026-05-27 21:47:50 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-05-31 21:50:25 -0700 |
| commit | df3ee3b3bbc327f570c5451666bbaf6cf8b4436a (patch) | |
| tree | 6812fc3cae9d84e6872d58b6e97d14815f23f088 | |
| parent | 85668fda932a5b8f15f649cf06411525a0e4c8ec (diff) | |
userfaultfd: refuse to __mfill_atomic_pte() for unsupported VMAs
__mfill_atomic_pte() unconditionally dereferences ops because there is an
assumption that VMAs that can undergo mfill_* operations are vetted on
registration and must have valid vm_uffd_ops.
Add a guard against potential bugs and make sure __mfill_atomic_pte()
bails out if ops is NULL.
Link: https://lore.kernel.org/20260527184751.4147364-3-rppt@kernel.org
Fixes: ad9ac3081332 ("userfaultfd: introduce vm_uffd_ops->alloc_folio()")
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Suggested-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: David CARLIER <devnexen@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michael Bommarito <michael.bommarito@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/userfaultfd.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index e5d2fb3ce2c1..2872c71bbf36 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -552,6 +552,11 @@ static int __mfill_atomic_pte(struct mfill_state *state, struct folio *folio; int ret; + if (!ops) { + VM_WARN_ONCE(1, "UFFDIO_COPY for unsupported VMA"); + return -EOPNOTSUPP; + } + folio = ops->alloc_folio(state->vma, state->dst_addr); if (!folio) return -ENOMEM; |