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[PATCH] mbind: fix verify_pages pte_page

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Strict mbind's check that pages already mapped are on right node has been
using pte_page without checking if pfn_valid, and without page_table_lock
to prevent spurious failures when try_to_unmap_one intervenes between the
pte_present and the pte_page.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Hugh Dickins 2005-06-21 17:15:06 -07:00 committed by Linus Torvalds
parent 400e65146c
commit 941150a326
1 changed files with 14 additions and 5 deletions
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19
mm/mempolicy.c
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@ -242,6 +242,9 @@ static int
verify_pages(struct mm_struct *mm,
unsigned long addr, unsigned long end, unsigned long *nodes)
{
int err = 0;
spin_lock(&mm->page_table_lock);
while (addr < end) {
struct page *p;
pte_t *pte;
@ -268,17 +271,23 @@ verify_pages(struct mm_struct *mm,
}
p = NULL;
pte = pte_offset_map(pmd, addr);
if (pte_present(*pte))
p = pte_page(*pte);
if (pte_present(*pte)) {
unsigned long pfn = pte_pfn(*pte);
if (pfn_valid(pfn))
p = pfn_to_page(pfn);
}
pte_unmap(pte);
if (p) {
unsigned nid = page_to_nid(p);
if (!test_bit(nid, nodes))
return -EIO;
if (!test_bit(nid, nodes)) {
err = -EIO;
break;
}
}
addr += PAGE_SIZE;
}
return 0;
spin_unlock(&mm->page_table_lock);
return err;
}
/* Step 1: check the range */