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-rw-r--r--mm/hugetlb.c32
1 files changed, 30 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 424b0ef..2d2ff5e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3984,6 +3984,9 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
unsigned long src_addr,
struct page **pagep)
{
+ struct address_space *mapping;
+ pgoff_t idx;
+ unsigned long size;
int vm_shared = dst_vma->vm_flags & VM_SHARED;
struct hstate *h = hstate_vma(dst_vma);
pte_t _dst_pte;
@@ -4021,13 +4024,24 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
__SetPageUptodate(page);
set_page_huge_active(page);
+ mapping = dst_vma->vm_file->f_mapping;
+ idx = vma_hugecache_offset(h, dst_vma, dst_addr);
+
/*
* If shared, add to page cache
*/
if (vm_shared) {
- struct address_space *mapping = dst_vma->vm_file->f_mapping;
- pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr);
+ size = i_size_read(mapping->host) >> huge_page_shift(h);
+ ret = -EFAULT;
+ if (idx >= size)
+ goto out_release_nounlock;
+ /*
+ * Serialization between remove_inode_hugepages() and
+ * huge_add_to_page_cache() below happens through the
+ * hugetlb_fault_mutex_table that here must be hold by
+ * the caller.
+ */
ret = huge_add_to_page_cache(page, mapping, idx);
if (ret)
goto out_release_nounlock;
@@ -4036,6 +4050,20 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
spin_lock(ptl);
+ /*
+ * Recheck the i_size after holding PT lock to make sure not
+ * to leave any page mapped (as page_mapped()) beyond the end
+ * of the i_size (remove_inode_hugepages() is strict about
+ * enforcing that). If we bail out here, we'll also leave a
+ * page in the radix tree in the vm_shared case beyond the end
+ * of the i_size, but remove_inode_hugepages() will take care
+ * of it as soon as we drop the hugetlb_fault_mutex_table.
+ */
+ size = i_size_read(mapping->host) >> huge_page_shift(h);
+ ret = -EFAULT;
+ if (idx >= size)
+ goto out_release_unlock;
+
ret = -EEXIST;
if (!huge_pte_none(huge_ptep_get(dst_pte)))
goto out_release_unlock;
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