From: Peter Xu <peterx@redhat.com> stable inclusion from stable-v6.6.30 commit f6c5d21db16a0910152ec8aa9d5a7aed72694505 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9NYY7 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit b76b46902c2d0395488c8412e1116c2486cdfcb2 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: mm/hugetlb.c [ Context conflicts with commit d5ea6f5f46c3 because it adds a new param in hugepage_subpool_put_pages() and hugetlb_acct_memory(). ] Signed-off-by: Liu Shixin <liushixin2@huawei.com> --- mm/hugetlb.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 2e6b210ae430..3b105856de6f 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3255,9 +3255,12 @@ struct folio *alloc_hugetlb_folio(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_folio_rsvd(hstate_index(h), pages_per_huge_page(h), folio); + spin_unlock_irq(&hugetlb_lock); + } } if (!memcg_charge_ret) -- 2.25.1