aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorWilliam Lee Irwin III <wli@holomorphy.com>2005-05-24 19:31:09 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-24 20:08:13 -0700
commitcafdd8ba08935d9b161bb781851dc4c0e6f70427 (patch)
treeee6a5305902cfd6abf818e398c538694db24dcb7
parentc33880aaddbbab1ccf36f4457ed1090621f2e39a (diff)
downloadlinux-cafdd8ba08935d9b161bb781851dc4c0e6f70427.tar.gz
[PATCH] try_to_unmap_cluster() passes out-of-bounds pte to pte_unmap()
try_to_unmap_cluster() does: for (pte = pte_offset_map(pmd, address); address < end; pte++, address += PAGE_SIZE) { ... } pte_unmap(pte); It may take a little staring to notice, but pte can actually fall off the end of the pte page in this iteration, which makes life difficult for kmap_atomic() and the users not expecting it to BUG(). Of course, we're somewhat lucky in that arithmetic elsewhere in the function guarantees that at least one iteration is made, lest this force larger rearrangements to be made. This issue and patch also apply to non-mm mainline and with trivial adjustments, at least two related kernels. Discovered during internal testing at Oracle. Signed-off-by: William Irwin <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--mm/rmap.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index a6203b4e127..9827409eb7c 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -626,7 +626,7 @@ static void try_to_unmap_cluster(unsigned long cursor,
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
- pte_t *pte;
+ pte_t *pte, *original_pte;
pte_t pteval;
struct page *page;
unsigned long address;
@@ -658,7 +658,7 @@ static void try_to_unmap_cluster(unsigned long cursor,
if (!pmd_present(*pmd))
goto out_unlock;
- for (pte = pte_offset_map(pmd, address);
+ for (original_pte = pte = pte_offset_map(pmd, address);
address < end; pte++, address += PAGE_SIZE) {
if (!pte_present(*pte))
@@ -694,7 +694,7 @@ static void try_to_unmap_cluster(unsigned long cursor,
(*mapcount)--;
}
- pte_unmap(pte);
+ pte_unmap(original_pte);
out_unlock:
spin_unlock(&mm->page_table_lock);
}