diff options
| author | Hugh Dickins | 2005-10-29 18:16:27 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2005-10-29 21:40:40 -0700 |
| commit | 705e87c0c3c38424f7f30556c85bc20e808d2f59 (patch) | |
| tree | 7a237e6266f4801385e1226cc497b47e3a2458bd /mm/mempolicy.c | |
| parent | 8f4e2101fd7df9031a754eedb82e2060b51f8c45 (diff) | |
[PATCH] mm: pte_offset_map_lock loops
Convert those common loops using page_table_lock on the outside and
pte_offset_map within to use just pte_offset_map_lock within instead.
These all hold mmap_sem (some exclusively, some not), so at no level can a
page table be whipped away from beneath them. But whereas pte_alloc loops
tested with the "atomic" pmd_present, these loops are testing with pmd_none,
which on i386 PAE tests both lower and upper halves.
That's now unsafe, so add a cast into pmd_none to test only the vital lower
half: we lose a little sensitivity to a corrupt middle directory, but not
enough to worry about. It appears that i386 and UML were the only
architectures vulnerable in this way, and pgd and pud no problem.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/mempolicy.c')
| -rw-r--r-- | mm/mempolicy.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 11d824f282f1..902d4c9eccdc 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -228,9 +228,9 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd, { pte_t *orig_pte; pte_t *pte; + spinlock_t *ptl; - spin_lock(&vma->vm_mm->page_table_lock); - orig_pte = pte = pte_offset_map(pmd, addr); + orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); do { unsigned long pfn; unsigned int nid; @@ -246,8 +246,7 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd, if (!node_isset(nid, *nodes)) break; } while (pte++, addr += PAGE_SIZE, addr != end); - pte_unmap(orig_pte); - spin_unlock(&vma->vm_mm->page_table_lock); + pte_unmap_unlock(orig_pte, ptl); return addr != end; } |