On Sat, Jul 30, 2022 at 05:35:37PM +0200, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 5.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
Hello,
I updated the patch for 5.18-stable, could you apply this?
Thanks, Naoya Horiguchi --- From: Naoya Horiguchi naoya.horiguchi@nec.com Date: Mon, 1 Aug 2022 15:09:17 +0900 Subject: [PATCH] mm/hugetlb: separate path for hwpoison entry in copy_hugetlb_page_range()
commit c2cb0dcce9dd8b748b6ca8bb8d4a389f2e232307 upstream.
Originally copy_hugetlb_page_range() handles migration entries and hwpoisoned entries in similar manner. But recently the related code path has more code for migration entries, and when is_writable_migration_entry() was converted to !is_readable_migration_entry(), hwpoison entries on source processes got to be unexpectedly updated (which is legitimate for migration entries, but not for hwpoison entries). This results in unexpected serious issues like kernel panic when forking processes with hwpoison entries in pmd.
Separate the if branch into one for hwpoison entries and one for migration entries.
[naoya.horiguchi: Resolved conflict to apply for 5.18-stable.]
Link: https://lkml.kernel.org/r/20220704013312.2415700-3-naoya.horiguchi@linux.dev Fixes: 6c287605fd56 ("mm: remember exclusively mapped anonymous pages with PG_anon_exclusive") Signed-off-by: Naoya Horiguchi naoya.horiguchi@nec.com Reviewed-by: Miaohe Lin linmiaohe@huawei.com Reviewed-by: Mike Kravetz mike.kravetz@oracle.com Reviewed-by: Muchun Song songmuchun@bytedance.com Cc: stable@vger.kernel.org [5.18] Cc: David Hildenbrand david@redhat.com Cc: Liu Shixin liushixin2@huawei.com Cc: Oscar Salvador osalvador@suse.de Cc: Yang Shi shy828301@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org --- mm/hugetlb.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 410bbb0aee32..0aa670addd8c 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4764,8 +4764,9 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, * sharing with another vma. */ ; - } else if (unlikely(is_hugetlb_entry_migration(entry) || - is_hugetlb_entry_hwpoisoned(entry))) { + } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) { + set_huge_pte_at(dst, addr, dst_pte, entry); + } else if (unlikely(is_hugetlb_entry_migration(entry))) { swp_entry_t swp_entry = pte_to_swp_entry(entry);
if (is_writable_migration_entry(swp_entry) && cow) {