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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: b1f9e87686 ("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>
This commit is contained in:
Peter Xu 2022-09-30 20:25:55 -04:00 committed by Andrew Morton
parent 28c5609fb2
commit 515778e2d7
3 changed files with 8 additions and 0 deletions
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4
mm/hugetlb.c
View File

@ -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);

2
mm/memory.c
View File

@ -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,

2
mm/mprotect.c
View File

@ -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();