From: Peter Xu peterx@redhat.com

mainline inclusion from mainline-v6.9-rc6 commit b76b46902c2d0395488c8412e1116c2486cdfcb2 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9QR5M CVE: CVE-2024-36000

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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There is a recent report on UFFDIO_COPY over hugetlb:

https://lore.kernel.org/all/000000000000ee06de0616177560@google.com/

350: lockdep_assert_held(&hugetlb_lock);

Should be an issue in hugetlb but triggered in an userfault context, where it goes into the unlikely path where two threads modifying the resv map together. Mike has a fix in that path for resv uncharge but it looks like the locking criteria was overlooked: hugetlb_cgroup_uncharge_folio_rsvd() will update the cgroup pointer, so it requires to be called with the lock held.

Link: https://lkml.kernel.org/r/20240417211836.2742593-3-peterx@redhat.com Fixes: 79aa925bf239 ("hugetlb_cgroup: fix reservation accounting") Signed-off-by: Peter Xu peterx@redhat.com Reported-by: syzbot+4b8077a5fccc61c385a1@syzkaller.appspotmail.com Reviewed-by: Mina Almasry almasrymina@google.com Cc: David Hildenbrand david@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org

Conflicts: mm/hugetlb.c [Conflicts due to page converts to folio.] Signed-off-by: Jinjiang Tu tujinjiang@huawei.com --- mm/hugetlb.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c index e04c21f735ad..e3746bcfc827 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2709,9 +2709,12 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,

rsv_adjust = hugepage_subpool_put_pages(spool, 1, info); hugetlb_acct_memory(h, -rsv_adjust, info); - if (deferred_reserve) + if (deferred_reserve) { + spin_lock_irq(&hugetlb_lock); hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h), pages_per_huge_page(h), page); + spin_unlock_irq(&hugetlb_lock); + } } return page;