[PATCH] hugetlb: fix linked list corruption in unmap_hugepage_range()
commit fe1668ae5b
causes kernel to oops with
libhugetlbfs test suite. The problem is that hugetlb pages can be shared
by multiple mappings. Multiple threads can fight over page->lru in the
unmap path and bad things happen. We now serialize __unmap_hugepage_range
to void concurrent linked list manipulation. Such serialization is also
needed for shared page table page on hugetlb area. This patch will fixed
the bug and also serve as a prepatch for shared page table.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -293,7 +293,7 @@ hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
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if (h_vm_pgoff >= h_pgoff)
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if (h_vm_pgoff >= h_pgoff)
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v_offset = 0;
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v_offset = 0;
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unmap_hugepage_range(vma,
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__unmap_hugepage_range(vma,
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vma->vm_start + v_offset, vma->vm_end);
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vma->vm_start + v_offset, vma->vm_end);
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}
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}
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}
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}
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@ -17,6 +17,7 @@ int hugetlb_sysctl_handler(struct ctl_table *, int, struct file *, void __user *
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int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
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int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
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int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct page **, struct vm_area_struct **, unsigned long *, int *, int);
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int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct page **, struct vm_area_struct **, unsigned long *, int *, int);
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void unmap_hugepage_range(struct vm_area_struct *, unsigned long, unsigned long);
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void unmap_hugepage_range(struct vm_area_struct *, unsigned long, unsigned long);
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void __unmap_hugepage_range(struct vm_area_struct *, unsigned long, unsigned long);
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int hugetlb_prefault(struct address_space *, struct vm_area_struct *);
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int hugetlb_prefault(struct address_space *, struct vm_area_struct *);
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int hugetlb_report_meminfo(char *);
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int hugetlb_report_meminfo(char *);
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int hugetlb_report_node_meminfo(int, char *);
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int hugetlb_report_node_meminfo(int, char *);
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22
mm/hugetlb.c
22
mm/hugetlb.c
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@ -356,8 +356,8 @@ nomem:
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return -ENOMEM;
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return -ENOMEM;
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}
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}
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void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
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void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
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unsigned long end)
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unsigned long end)
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{
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{
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struct mm_struct *mm = vma->vm_mm;
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struct mm_struct *mm = vma->vm_mm;
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unsigned long address;
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unsigned long address;
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@ -398,6 +398,24 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
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}
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}
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}
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}
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void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
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unsigned long end)
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{
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/*
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* It is undesirable to test vma->vm_file as it should be non-null
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* for valid hugetlb area. However, vm_file will be NULL in the error
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* cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
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* do_mmap_pgoff() nullifies vma->vm_file before calling this function
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* to clean up. Since no pte has actually been setup, it is safe to
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* do nothing in this case.
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*/
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if (vma->vm_file) {
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spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
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__unmap_hugepage_range(vma, start, end);
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spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
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}
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}
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static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
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static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
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unsigned long address, pte_t *ptep, pte_t pte)
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unsigned long address, pte_t *ptep, pte_t pte)
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{
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{
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