diff options
| author | Hugh Dickins <hughd@google.com> | 2023-06-08 18:26:04 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-06-19 16:19:15 -0700 |
| commit | 3622d3cde30898c1b6eafde281c122b994718c58 (patch) | |
| tree | 7568d3b856fc1c6e9947868953a5f7b826b41daf /mm/userfaultfd.c | |
| parent | 2b683a4ff6ee091d5764ad867fbfae65f80cfefb (diff) | |
| download | lwn-3622d3cde30898c1b6eafde281c122b994718c58.tar.gz lwn-3622d3cde30898c1b6eafde281c122b994718c58.zip | |
mm/userfaultfd: allow pte_offset_map_lock() to fail
mfill_atomic_install_pte() and mfill_atomic_pte_zeropage() treat failed
pte_offset_map_lock() as -EAGAIN, which mfill_atomic() already returns to
user for a similar race.
Link: https://lkml.kernel.org/r/50cf3930-1bfa-4de9-a079-3da47b7ce17b@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/userfaultfd.c')
| -rw-r--r-- | mm/userfaultfd.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index e97a0b4889fc..5fd787158c70 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -76,7 +76,10 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd, if (flags & MFILL_ATOMIC_WP) _dst_pte = pte_mkuffd_wp(_dst_pte); + ret = -EAGAIN; dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); + if (!dst_pte) + goto out; if (vma_is_shmem(dst_vma)) { /* serialize against truncate with the page table lock */ @@ -121,6 +124,7 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd, ret = 0; out_unlock: pte_unmap_unlock(dst_pte, ptl); +out: return ret; } @@ -212,7 +216,10 @@ static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd, _dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr), dst_vma->vm_page_prot)); + ret = -EAGAIN; dst_pte = pte_offset_map_lock(dst_vma->vm_mm, dst_pmd, dst_addr, &ptl); + if (!dst_pte) + goto out; if (dst_vma->vm_file) { /* the shmem MAP_PRIVATE case requires checking the i_size */ inode = dst_vma->vm_file->f_inode; @@ -231,6 +238,7 @@ static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd, ret = 0; out_unlock: pte_unmap_unlock(dst_pte, ptl); +out: return ret; } |