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authorHugh Dickins <hugh@veritas.com>2005-06-21 20:15:06 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-21 21:46:19 -0400
commit941150a326be88af245034ef4b3e9fa00229aa2d (patch)
tree03a058776dccd007150a3f57b1f36bf63b8f6a5d
parent400e65146c428d2ef677a927786fda2cec545a76 (diff)
[PATCH] mbind: fix verify_pages pte_page
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>
-rw-r--r--mm/mempolicy.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 39252c732db2..c512cc911e22 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -242,6 +242,9 @@ static int
242verify_pages(struct mm_struct *mm, 242verify_pages(struct mm_struct *mm,
243 unsigned long addr, unsigned long end, unsigned long *nodes) 243 unsigned long addr, unsigned long end, unsigned long *nodes)
244{ 244{
245 int err = 0;
246
247 spin_lock(&mm->page_table_lock);
245 while (addr < end) { 248 while (addr < end) {
246 struct page *p; 249 struct page *p;
247 pte_t *pte; 250 pte_t *pte;
@@ -268,17 +271,23 @@ verify_pages(struct mm_struct *mm,
268 } 271 }
269 p = NULL; 272 p = NULL;
270 pte = pte_offset_map(pmd, addr); 273 pte = pte_offset_map(pmd, addr);
271 if (pte_present(*pte)) 274 if (pte_present(*pte)) {
272 p = pte_page(*pte); 275 unsigned long pfn = pte_pfn(*pte);
276 if (pfn_valid(pfn))
277 p = pfn_to_page(pfn);
278 }
273 pte_unmap(pte); 279 pte_unmap(pte);
274 if (p) { 280 if (p) {
275 unsigned nid = page_to_nid(p); 281 unsigned nid = page_to_nid(p);
276 if (!test_bit(nid, nodes)) 282 if (!test_bit(nid, nodes)) {
277 return -EIO; 283 err = -EIO;
284 break;
285 }
278 } 286 }
279 addr += PAGE_SIZE; 287 addr += PAGE_SIZE;
280 } 288 }
281 return 0; 289 spin_unlock(&mm->page_table_lock);
290 return err;
282} 291}
283 292
284/* Step 1: check the range */ 293/* Step 1: check the range */