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authorMiaohe Lin <[email protected]>2024-07-08 10:51:27 +0800
committerAndrew Morton <[email protected]>2024-07-09 15:41:10 -0700
commit5596d9e8b553dacb0ac34bcf873cbbfb16c3ba3e (patch)
treed175cfe1e803bb9cd168adecdde45709126cd61a
parent24be02a42181f0707be0498045c4c4b13273b16d (diff)
mm/hugetlb: fix potential race in __update_and_free_hugetlb_folio()
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/[email protected] Fixes: 32c877191e02 ("hugetlb: do not clear hugetlb dtor until allocating vmemmap") Signed-off-by: Miaohe Lin <[email protected]> Acked-by: Muchun Song <[email protected]> Reviewed-by: Oscar Salvador <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
-rw-r--r--mm/hugetlb.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 2afb70171b76..fe44324d6383 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1726,13 +1726,6 @@ static void __update_and_free_hugetlb_folio(struct hstate *h,
}
/*
- * 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_folio(struct hstate *h,
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);
/*