The patch titled
do_wp_page: fix regression with execute in place
has been added to the -mm tree. Its filename is
do_wp_page-fix-regression-with-execute-in-place.patch
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------------------------------------------------------
Subject: do_wp_page: fix regression with execute in place
From: Carsten Otte <cotte@xxxxxxxxxx>
Fix do_wp_page for VM_MIXEDMAP mappings.
In the case where pfn_valid returns 0 for a pfn at the beginning of
do_wp_page and the mapping is not shared writable, the code branches to
label `gotten:' with old_page == NULL.
In case the vma is locked (vma->vm_flags & VM_LOCKED), lock_page,
clear_page_mlock, and unlock_page try to access the old_page.
This patch checks whether old_page is valid before it is dereferenced.
The regression was introduced by
commit b291f000393f5a0b679012b39d79fbc85c018233
Author: Nick Piggin <npiggin@xxxxxxx>
AuthorDate: Sat Oct 18 20:26:44 2008 -0700
Commit: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
CommitDate: Mon Oct 20 08:52:30 2008 -0700
mlock: mlocked pages are unevictable
Signed-off-by: Carsten Otte <cotte@xxxxxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx> [2.6.28.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/memory.c~do_wp_page-fix-regression-with-execute-in-place mm/memory.c
--- a/mm/memory.c~do_wp_page-fix-regression-with-execute-in-place
+++ a/mm/memory.c
@@ -1999,7 +1999,7 @@ gotten:
* Don't let another task, with possibly unlocked vma,
* keep the mlocked page.
*/
- if (vma->vm_flags & VM_LOCKED) {
+ if ((vma->vm_flags & VM_LOCKED) && old_page) {
lock_page(old_page); /* for LRU manipulation */
clear_page_mlock(old_page);
unlock_page(old_page);
_
Patches currently in -mm which might be from cotte@xxxxxxxxxx are
linux-next.patch
do_wp_page-fix-regression-with-execute-in-place.patch
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