[merged mm-hotfixes-stable] mm-hugetlb-fix-potential-race-in-__update_and_free_hugetlb_folio.patch removed from -mm tree

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The quilt patch titled
     Subject: mm/hugetlb: fix potential race in __update_and_free_hugetlb_folio()
has been removed from the -mm tree.  Its filename was
     mm-hugetlb-fix-potential-race-in-__update_and_free_hugetlb_folio.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/hugetlb: fix potential race in __update_and_free_hugetlb_folio()
Date: Mon, 8 Jul 2024 10:51:27 +0800

There is a potential race between __update_and_free_hugetlb_folio() and
try_memory_failure_hugetlb():

 CPU1					CPU2
 __update_and_free_hugetlb_folio	try_memory_failure_hugetlb
					 folio_test_hugetlb
					  -- It's still hugetlb folio.
  folio_clear_hugetlb_hwpoison
  					  spin_lock_irq(&hugetlb_lock);
					   __get_huge_page_for_hwpoison
					    folio_set_hugetlb_hwpoison
					  spin_unlock_irq(&hugetlb_lock);
  spin_lock_irq(&hugetlb_lock);
  __folio_clear_hugetlb(folio);
   -- Hugetlb flag is cleared but too late.
  spin_unlock_irq(&hugetlb_lock);

When the above race occurs, raw error page info will be leaked.  Even
worse, raw error pages won't have hwpoisoned flag set and hit
pcplists/buddy.  Fix this issue by deferring
folio_clear_hugetlb_hwpoison() until __folio_clear_hugetlb() is done.  So
all raw error pages will have hwpoisoned flag set.

Link: https://lkml.kernel.org/r/20240708025127.107713-1-linmiaohe@xxxxxxxxxx
Fixes: 32c877191e02 ("hugetlb: do not clear hugetlb dtor until allocating vmemmap")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Acked-by: Muchun Song <muchun.song@xxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/hugetlb.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/mm/hugetlb.c~mm-hugetlb-fix-potential-race-in-__update_and_free_hugetlb_folio
+++ a/mm/hugetlb.c
@@ -1726,13 +1726,6 @@ static void __update_and_free_hugetlb_fo
 	}
 
 	/*
-	 * Move PageHWPoison flag from head page to the raw error pages,
-	 * which makes any healthy subpages reusable.
-	 */
-	if (unlikely(folio_test_hwpoison(folio)))
-		folio_clear_hugetlb_hwpoison(folio);
-
-	/*
 	 * If vmemmap pages were allocated above, then we need to clear the
 	 * hugetlb flag under the hugetlb lock.
 	 */
@@ -1742,6 +1735,13 @@ static void __update_and_free_hugetlb_fo
 		spin_unlock_irq(&hugetlb_lock);
 	}
 
+	/*
+	 * Move PageHWPoison flag from head page to the raw error pages,
+	 * which makes any healthy subpages reusable.
+	 */
+	if (unlikely(folio_test_hwpoison(folio)))
+		folio_clear_hugetlb_hwpoison(folio);
+
 	folio_ref_unfreeze(folio, 1);
 
 	/*
_

Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are

mm-memory-failure-remove-obsolete-mf_msg_different_compound.patch





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