mm: fix crashes from mbind() merging vmas
commitd05f0cdcbe
upstream. In v2.6.34 commit9d8cebd4bc
("mm: fix mbind vma merge problem") introduced vma merging to mbind(), but it should have also changed the convention of passing start vma from queue_pages_range() (formerly check_range()) to new_vma_page(): vma merging may have already freed that structure, resulting in BUG at mm/mempolicy.c:1738 and probably worse crashes. Fixes:9d8cebd4bc
("mm: fix mbind vma merge problem") Reported-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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93ab3fb918
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@ -653,19 +653,18 @@ static unsigned long change_prot_numa(struct vm_area_struct *vma,
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* @nodes and @flags,) it's isolated and queued to the pagelist which is
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* passed via @private.)
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*/
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static struct vm_area_struct *
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static int
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queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
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const nodemask_t *nodes, unsigned long flags, void *private)
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{
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int err;
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struct vm_area_struct *first, *vma, *prev;
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int err = 0;
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struct vm_area_struct *vma, *prev;
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first = find_vma(mm, start);
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if (!first)
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return ERR_PTR(-EFAULT);
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vma = find_vma(mm, start);
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if (!vma)
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return -EFAULT;
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prev = NULL;
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for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) {
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for (; vma && vma->vm_start < end; vma = vma->vm_next) {
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unsigned long endvma = vma->vm_end;
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if (endvma > end)
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@ -675,9 +674,9 @@ queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
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if (!(flags & MPOL_MF_DISCONTIG_OK)) {
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if (!vma->vm_next && vma->vm_end < end)
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return ERR_PTR(-EFAULT);
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return -EFAULT;
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if (prev && prev->vm_end < vma->vm_start)
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return ERR_PTR(-EFAULT);
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return -EFAULT;
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}
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if (flags & MPOL_MF_LAZY) {
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@ -691,15 +690,13 @@ queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
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err = queue_pages_pgd_range(vma, start, endvma, nodes,
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flags, private);
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if (err) {
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first = ERR_PTR(err);
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if (err)
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break;
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}
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}
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next:
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prev = vma;
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}
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return first;
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return err;
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}
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/*
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@ -1184,16 +1181,17 @@ out:
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/*
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* Allocate a new page for page migration based on vma policy.
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* Start assuming that page is mapped by vma pointed to by @private.
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* Start by assuming the page is mapped by the same vma as contains @start.
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* Search forward from there, if not. N.B., this assumes that the
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* list of pages handed to migrate_pages()--which is how we get here--
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* is in virtual address order.
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*/
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static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
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static struct page *new_page(struct page *page, unsigned long start, int **x)
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{
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struct vm_area_struct *vma = (struct vm_area_struct *)private;
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struct vm_area_struct *vma;
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unsigned long uninitialized_var(address);
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vma = find_vma(current->mm, start);
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while (vma) {
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address = page_address_in_vma(page, vma);
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if (address != -EFAULT)
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@ -1223,7 +1221,7 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
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return -ENOSYS;
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}
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static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
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static struct page *new_page(struct page *page, unsigned long start, int **x)
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{
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return NULL;
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}
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@ -1233,7 +1231,6 @@ static long do_mbind(unsigned long start, unsigned long len,
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unsigned short mode, unsigned short mode_flags,
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nodemask_t *nmask, unsigned long flags)
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{
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struct vm_area_struct *vma;
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struct mm_struct *mm = current->mm;
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struct mempolicy *new;
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unsigned long end;
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@ -1299,11 +1296,9 @@ static long do_mbind(unsigned long start, unsigned long len,
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if (err)
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goto mpol_out;
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vma = queue_pages_range(mm, start, end, nmask,
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err = queue_pages_range(mm, start, end, nmask,
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flags | MPOL_MF_INVERT, &pagelist);
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err = PTR_ERR(vma); /* maybe ... */
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if (!IS_ERR(vma))
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if (!err)
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err = mbind_range(mm, start, end, new);
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if (!err) {
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@ -1311,9 +1306,8 @@ static long do_mbind(unsigned long start, unsigned long len,
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if (!list_empty(&pagelist)) {
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WARN_ON_ONCE(flags & MPOL_MF_LAZY);
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nr_failed = migrate_pages(&pagelist, new_vma_page,
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(unsigned long)vma,
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MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
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nr_failed = migrate_pages(&pagelist, new_page,
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start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND);
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if (nr_failed)
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putback_movable_pages(&pagelist);
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}
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