]> www.infradead.org Git - users/hch/xfs.git/commit
mm/hugetlb: fix potential race in __update_and_free_hugetlb_folio()
authorMiaohe Lin <linmiaohe@huawei.com>
Mon, 8 Jul 2024 02:51:27 +0000 (10:51 +0800)
committerAndrew Morton <akpm@linux-foundation.org>
Tue, 9 Jul 2024 22:41:10 +0000 (15:41 -0700)
commit5596d9e8b553dacb0ac34bcf873cbbfb16c3ba3e
treed175cfe1e803bb9cd168adecdde45709126cd61a
parent24be02a42181f0707be0498045c4c4b13273b16d
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>
mm/hugetlb.c