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Commit bbeb34062fbad287c949a945a516a0c15b179993

Authored by Huang Ying
Committed by Avi Kivity
1 parent 6c3f604117

KVM: Fix a race condition for usage of is_hwpoison_address() 

is_hwpoison_address accesses the page table, so the caller must hold
current->mm->mmap_sem in read mode. So fix its usage in hva_to_pfn of
kvm accordingly.

Comment is_hwpoison_address to remind other users.

Reported-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

Showing 2 changed files with 5 additions and 1 deletions Side-by-side Diff

... ... @@ -1298,6 +1298,9 @@
1298 1298 return ret;
1299 1299 }
1300 1300  
  1301 +/*
  1302 + * The caller must hold current->mm->mmap_sem in read mode.
  1303 + */
1301 1304 int is_hwpoison_address(unsigned long addr)
1302 1305 {
1303 1306 pgd_t *pgdp;
... ... @@ -947,12 +947,13 @@
947 947 if (unlikely(npages != 1)) {
948 948 struct vm_area_struct *vma;
949 949  
  950 + down_read(&current->mm->mmap_sem);
950 951 if (is_hwpoison_address(addr)) {
  952 + up_read(&current->mm->mmap_sem);
951 953 get_page(hwpoison_page);
952 954 return page_to_pfn(hwpoison_page);
953 955 }
954 956  
955   - down_read(&current->mm->mmap_sem);
956 957 vma = find_vma(current->mm, addr);
957 958  
958 959 if (vma == NULL || addr < vma->vm_start ||