On 22.02.24 09:08, Qi Zheng wrote:
After ptep_clear_flush(), if we find that src_folio is pinned we will fail
UFFDIO_MOVE and put src_folio back to src_pte entry, but the change to
src_folio->{mapping,index} is not restored in this process. This is not
what we expected, so fix it.
Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI")
Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
---
mm/userfaultfd.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 4744d6a96f96..503ea77c81aa 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -1008,9 +1008,6 @@ static int move_present_pte(struct mm_struct *mm,
goto out;
}
- folio_move_anon_rmap(src_folio, dst_vma);
- WRITE_ONCE(src_folio->index, linear_page_index(dst_vma, dst_addr));
-
orig_src_pte = ptep_clear_flush(src_vma, src_addr, src_pte);
/* Folio got pinned from under us. Put it back and fail the move. */
if (folio_maybe_dma_pinned(src_folio)) {
@@ -1019,6 +1016,9 @@ static int move_present_pte(struct mm_struct *mm,
goto out;
}
+ folio_move_anon_rmap(src_folio, dst_vma);
+ WRITE_ONCE(src_folio->index, linear_page_index(dst_vma, dst_addr));
+
orig_dst_pte = mk_pte(&src_folio->page, dst_vma->vm_page_prot);
/* Follow mremap() behavior and treat the entry dirty after the move */
orig_dst_pte = pte_mkwrite(pte_mkdirty(orig_dst_pte), dst_vma);
Indeed, LGTM.
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Cheers,
David / dhildenb
