mm: don't call pte_unmap() against an improper pte
There are some places where we do like:
pte = pte_map();
do {
(do break in some conditions)
} while (pte++, ...);
pte_unmap(pte - 1);
But if the loop breaks at the first loop, pte_unmap() unmaps invalid pte.
This patch is a fix for this problem.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewd-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory.c b/mm/memory.c
index 7e91b5f..60ea601 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -641,6 +641,7 @@
pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
unsigned long addr, unsigned long end)
{
+ pte_t *orig_src_pte, *orig_dst_pte;
pte_t *src_pte, *dst_pte;
spinlock_t *src_ptl, *dst_ptl;
int progress = 0;
@@ -654,6 +655,8 @@
src_pte = pte_offset_map_nested(src_pmd, addr);
src_ptl = pte_lockptr(src_mm, src_pmd);
spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
+ orig_src_pte = src_pte;
+ orig_dst_pte = dst_pte;
arch_enter_lazy_mmu_mode();
do {
@@ -677,9 +680,9 @@
arch_leave_lazy_mmu_mode();
spin_unlock(src_ptl);
- pte_unmap_nested(src_pte - 1);
+ pte_unmap_nested(orig_src_pte);
add_mm_rss(dst_mm, rss[0], rss[1]);
- pte_unmap_unlock(dst_pte - 1, dst_ptl);
+ pte_unmap_unlock(orig_dst_pte, dst_ptl);
cond_resched();
if (addr != end)
goto again;
@@ -1820,10 +1823,10 @@
token = pmd_pgtable(*pmd);
do {
- err = fn(pte, token, addr, data);
+ err = fn(pte++, token, addr, data);
if (err)
break;
- } while (pte++, addr += PAGE_SIZE, addr != end);
+ } while (addr += PAGE_SIZE, addr != end);
arch_leave_lazy_mmu_mode();