From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org, surenb@google.com
Cc: Sasha Levin <sashal@kernel.org>
Subject: Re: [PATCH 6.12.y] mm: fix kernel BUG when userfaultfd_move encounters swapcache
Date: Thu, 13 Mar 2025 05:01:33 -0400 [thread overview]
Message-ID: <20250312204738-b4e540aab6e495cb@stable.kernel.org> (raw)
In-Reply-To: <20250310185747.1238197-1-surenb@google.com>
[ Sasha's backport helper bot ]
Hi,
Summary of potential issues:
⚠️ Found matching upstream commit but patch is missing proper reference to it
ℹ️ Patch is missing in 6.13.y (ignore if backport was sent)
⚠️ Commit missing in all newer stable branches
Found matching upstream commit: c50f8e6053b0503375c2975bf47f182445aebb4c
WARNING: Author mismatch between patch and found commit:
Backport author: Suren Baghdasaryan<surenb@google.com>
Commit author: Barry Song<v-songbaohua@oppo.com>
Status in newer kernel trees:
6.13.y | Not found
Note: The patch differs from the upstream commit:
---
1: c50f8e6053b05 ! 1: 8c54f12bcedaa mm: fix kernel BUG when userfaultfd_move encounters swapcache
@@ Commit message
Cc: Tangquan Zheng <zhengtangquan@oppo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+ (cherry picked from commit c50f8e6053b0503375c2975bf47f182445aebb4c)
+ [surenb: resolved merged conflict caused by the difference in
+ move_swap_pte() arguments]
+ Signed-off-by: Suren Baghdasaryan <surenb@google.com>
## mm/userfaultfd.c ##
@@
@@ mm/userfaultfd.c: static int move_present_pte(struct mm_struct *mm,
unsigned long dst_addr, unsigned long src_addr,
pte_t *dst_pte, pte_t *src_pte,
pte_t orig_dst_pte, pte_t orig_src_pte,
- pmd_t *dst_pmd, pmd_t dst_pmdval,
- spinlock_t *dst_ptl, spinlock_t *src_ptl)
+ spinlock_t *dst_ptl, spinlock_t *src_ptl,
+ struct folio *src_folio)
@@ mm/userfaultfd.c: static int move_present_pte(struct mm_struct *mm,
-
double_pt_lock(dst_ptl, src_ptl);
- if (!is_pte_pages_stable(dst_pte, src_pte, orig_dst_pte, orig_src_pte,
+ if (!pte_same(ptep_get(src_pte), orig_src_pte) ||
@@ mm/userfaultfd.c: static int move_swap_pte(struct mm_struct *mm,
return -EAGAIN;
}
@@ mm/userfaultfd.c: static int move_pages_pte(struct mm_struct *mm, pmd_t *dst_pmd
pte_t src_folio_pte;
spinlock_t *src_ptl, *dst_ptl;
@@ mm/userfaultfd.c: static int move_pages_pte(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd,
- orig_dst_pte, orig_src_pte, dst_pmd,
- dst_pmdval, dst_ptl, src_ptl, src_folio);
+ orig_dst_pte, orig_src_pte,
+ dst_ptl, src_ptl, src_folio);
} else {
+ struct folio *folio = NULL;
+
@@ mm/userfaultfd.c: static int move_pages_pte(struct mm_struct *mm, pmd_t *dst_pmd
goto out;
}
-- err = move_swap_pte(mm, dst_addr, src_addr, dst_pte, src_pte,
-- orig_dst_pte, orig_src_pte, dst_pmd,
-- dst_pmdval, dst_ptl, src_ptl);
+- err = move_swap_pte(mm, dst_addr, src_addr,
+- dst_pte, src_pte,
+- orig_dst_pte, orig_src_pte,
+- dst_ptl, src_ptl);
+ if (!pte_swp_exclusive(orig_src_pte)) {
+ err = -EBUSY;
+ goto out;
@@ mm/userfaultfd.c: static int move_pages_pte(struct mm_struct *mm, pmd_t *dst_pmd
+ }
+ }
+ err = move_swap_pte(mm, dst_vma, dst_addr, src_addr, dst_pte, src_pte,
-+ orig_dst_pte, orig_src_pte, dst_pmd, dst_pmdval,
++ orig_dst_pte, orig_src_pte,
+ dst_ptl, src_ptl, src_folio);
}
---
Results of testing on various branches:
| Branch | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.12.y | Success | Success |
prev parent reply other threads:[~2025-03-13 9:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-09 18:16 FAILED: patch "[PATCH] mm: fix kernel BUG when userfaultfd_move encounters swapcache" failed to apply to 6.12-stable tree gregkh
2025-03-10 18:57 ` [PATCH 6.12.y] mm: fix kernel BUG when userfaultfd_move encounters swapcache Suren Baghdasaryan
2025-03-13 9:01 ` Sasha Levin [this message]
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