| Message ID | 20240708025127.107713-1-linmiaohe@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/hugetlb: fix potential race in __update_and_free_hugetlb_folio() | expand |
> On Jul 8, 2024, at 10:51, Miaohe Lin <linmiaohe@huawei.com> wrote: > > 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 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. > > 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> Thanks.
On Mon, Jul 08, 2024 at 10:51:27AM +0800, Miaohe Lin wrote: > 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 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. > > Fixes: 32c877191e02 ("hugetlb: do not clear hugetlb dtor until allocating vmemmap") > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > Cc: <stable@vger.kernel.org> Reviewed-by: Oscar Salvador <osalvador@suse.de>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 61847f799b6a..63a2f1132a81 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1729,13 +1729,6 @@ static void __update_and_free_hugetlb_folio(struct hstate *h, return; } - /* - * 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. @@ -1746,6 +1739,13 @@ 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); /*
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 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. Fixes: 32c877191e02 ("hugetlb: do not clear hugetlb dtor until allocating vmemmap") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: <stable@vger.kernel.org> --- mm/hugetlb.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)