diff options
| author | Miaohe Lin <linmiaohe@huawei.com> | 2024-07-08 10:51:27 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-07-09 15:41:10 -0700 |
| commit | 5596d9e8b553dacb0ac34bcf873cbbfb16c3ba3e (patch) | |
| tree | d175cfe1e803bb9cd168adecdde45709126cd61a /mm/hugetlb.c | |
| parent | 24be02a42181f0707be0498045c4c4b13273b16d (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/20240708025127.107713-1-linmiaohe@huawei.com
Fixes: 32c877191e02 ("hugetlb: do not clear hugetlb dtor until allocating vmemmap")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 14 |
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); /* |