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authorJohannes Weiner <hannes@saeurebad.de>2008-04-28 02:11:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-28 08:58:16 -0700
commit556637cdabcd5918c7d4a1a2679b8f86fc81e891 (patch)
treea5bb95b50e88535966af3ad49017196b757fca64 /mm/pagewalk.c
parentf022bfd58253099102218db5249220a7f4787114 (diff)
downloadlinux-556637cdabcd5918c7d4a1a2679b8f86fc81e891.tar.gz
mm: fix possible off-by-one in walk_pte_range()
After the loop in walk_pte_range() pte might point to the first address after the pmd it walks. The pte_unmap() is then applied to something bad. Spotted by Roel Kluin and Andreas Schwab. Signed-off-by: Johannes Weiner <hannes@saeurebad.de> Cc: Roel Kluin <12o3l@tiscali.nl> Cc: Andreas Schwab <schwab@suse.de> Acked-by: Matt Mackall <mpm@selenic.com> Acked-by: Mikael Pettersson <mikpe@it.uu.se> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/pagewalk.c')
-rw-r--r--mm/pagewalk.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 1cf1417ef8b..0afd2387e50 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -9,11 +9,15 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
int err = 0;
pte = pte_offset_map(pmd, addr);
- do {
+ for (;;) {
err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, private);
if (err)
break;
- } while (pte++, addr += PAGE_SIZE, addr != end);
+ addr += PAGE_SIZE;
+ if (addr == end)
+ break;
+ pte++;
+ }
pte_unmap(pte);
return err;