mm/uffd: fix warning without PTE_MARKER_UFFD_WP compiled in

When PTE_MARKER_UFFD_WP not configured, it's still possible to reach pte
marker code and trigger an warning. Add a few CONFIG_PTE_MARKER_UFFD_WP
ifdefs to make sure the code won't be reached when not compiled in.

Link: https://lkml.kernel.org/r/YzeR+R6b4bwBlBHh@x1n
Fixes: b381dbf5e6bc ("mm/uffd: enable write protection for shmem & hugetlbfs")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: <syzbot+2b9b4f0895be09a6dec3@syzkaller.appspotmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Edward Liaw <edliaw@google.com>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 41d3aa0778373bbef00672fed64d904730caafc9..9a910612336dad400ac604432b0979d5ce40ff52 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5096,6 +5096,7 @@ static void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct
                 * unmapped and its refcount is dropped, so just clear pte here.
                 */
                if (unlikely(!pte_present(pte))) {
+#ifdef CONFIG_PTE_MARKER_UFFD_WP
                        /*
                         * If the pte was wr-protected by uffd-wp in any of the
                         * swap forms, meanwhile the caller does not want to
@@ -5107,6 +5108,7 @@ static void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct
                                set_huge_pte_at(mm, address, ptep,
                                                make_pte_marker(PTE_MARKER_UFFD_WP));
                        else
+#endif
                                huge_pte_clear(mm, address, ptep, sz);
                        spin_unlock(ptl);
                        continue;
@@ -5135,11 +5137,13 @@ static void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct
                tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
                if (huge_pte_dirty(pte))
                        set_page_dirty(page);
+#ifdef CONFIG_PTE_MARKER_UFFD_WP
                /* Leave a uffd-wp pte marker if needed */
                if (huge_pte_uffd_wp(pte) &&
                    !(zap_flags & ZAP_FLAG_DROP_MARKER))
                        set_huge_pte_at(mm, address, ptep,
                                        make_pte_marker(PTE_MARKER_UFFD_WP));
+#endif
                hugetlb_count_sub(pages_per_huge_page(h), mm);
                page_remove_rmap(page, vma, true);
 

diff --git a/mm/memory.c b/mm/memory.c
index df678fa30cdb9143e85d7e30bab57acda9121a8c..2c7723ea43714635ba9cc8dd6f1bb8529a13c367 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1393,10 +1393,12 @@ zap_install_uffd_wp_if_needed(struct vm_area_struct *vma,
                              unsigned long addr, pte_t *pte,
                              struct zap_details *details, pte_t pteval)
 {
+#ifdef CONFIG_PTE_MARKER_UFFD_WP
        if (zap_drop_file_uffd_wp(details))
                return;
 
        pte_install_uffd_wp_if_needed(vma, addr, pte, pteval);
+#endif
 }
 
 static unsigned long zap_pte_range(struct mmu_gather *tlb,

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 461dcbd4f21a6f9aa2aa910cad8ccaa7ec6dc0ea..668bfaa6ed2aebdbc64182e7d2c8a007a2d4bae7 100644 (file)
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -267,6 +267,7 @@ static unsigned long change_pte_range(struct mmu_gather *tlb,
                } else {
                        /* It must be an none page, or what else?.. */
                        WARN_ON_ONCE(!pte_none(oldpte));
+#ifdef CONFIG_PTE_MARKER_UFFD_WP
                        if (unlikely(uffd_wp && !vma_is_anonymous(vma))) {
                                /*
                                 * For file-backed mem, we need to be able to
@@ -278,6 +279,7 @@ static unsigned long change_pte_range(struct mmu_gather *tlb,
                                           make_pte_marker(PTE_MARKER_UFFD_WP));
                                pages++;
                        }
+#endif
                }
        } while (pte++, addr += PAGE_SIZE, addr != end);
        arch_leave_lazy_mmu_mode();