mm/uffd: fix warning without PTE_MARKER_UFFD_WP compiled in

commit 515778e2d790652a38a24554fdb7f21420d91efc upstream.

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: b1f9e876862d ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b6b5945bd08fc43f4e8d2934d62472c1ef8927a9..606fff4ab50fb1f3052a341f174a7a4df7b5b936 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5050,6 +5050,7 @@ 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
@@ -5061,6 +5062,7 @@ 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;
@@ -5089,11 +5091,13 @@ 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 e644f6fad3892ceff08420a3e737a6f1f90c8888..9658a9abf7c0d30822956bb224420a50caad9d67 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1385,10 +1385,12 @@ 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 0d38d5b6376219c958f47e7fd1de17394b4caf39..6bc74c67407e76a8bfff9d35ff83ee69191f8db9 100644 (file)
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -222,6 +222,7 @@ 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
@@ -233,6 +234,7 @@ 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();