The patch titled
Subject: mm/hugetlb: use hugetlb_pte_stable in migration race check
has been added to the -mm mm-unstable branch. Its filename is
mm-hugetlb-use-hugetlb_pte_stable-in-migration-race-check.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb-use-hugetlb_pte_stable-in-migration-race-check.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Peter Xu <peterx@xxxxxxxxxx>
Subject: mm/hugetlb: use hugetlb_pte_stable in migration race check
Date: Tue, 4 Oct 2022 15:33:59 -0400
After hugetlb_pte_stable() introduced, we can also rewrite the migration
race condition against page allocation to use the new helper too.
Link: https://lkml.kernel.org/r/20221004193400.110155-3-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Nadav Amit <nadav.amit@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
--- a/mm/hugetlb.c~mm-hugetlb-use-hugetlb_pte_stable-in-migration-race-check
+++ a/mm/hugetlb.c
@@ -5623,11 +5623,10 @@ static vm_fault_t hugetlb_no_page(struct
* here. Before returning error, get ptl and make
* sure there really is no pte entry.
*/
- ptl = huge_pte_lock(h, mm, ptep);
- ret = 0;
- if (huge_pte_none(huge_ptep_get(ptep)))
+ if (hugetlb_pte_stable(h, mm, ptep, old_pte))
ret = vmf_error(PTR_ERR(page));
- spin_unlock(ptl);
+ else
+ ret = 0;
goto out;
}
clear_huge_page(page, address, pages_per_huge_page(h));
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-uffd-fix-warning-without-pte_marker_uffd_wp-compiled-in.patch
mm-hugetlb-fix-race-condition-of-uffd-missing-minor-handling.patch
mm-hugetlb-use-hugetlb_pte_stable-in-migration-race-check.patch
mm-selftest-uffd-explain-the-write-missing-fault-check.patch
