diff options
| author | Carsten Otte <cotte@de.ibm.com> | 2009-02-04 15:12:16 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-02-12 09:50:22 -0800 |
| commit | 8c47f86fb53485e298ed154eb5c0ca0a89b85a24 (patch) | |
| tree | 7f8332f8c11999de0c0eddc982bfebbe03bd4354 /mm | |
| parent | 3bb90b5b5c86949bc3be417eea1eb85f10263098 (diff) | |
do_wp_page: fix regression with execute in place
commit ab92661d5d9514647346047f30f67a7f35ffea67 upstream.
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 "mlock: mlocked pages are unevictable"
(commit b291f000393f5a0b679012b39d79fbc85c018233).
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c index 164951c4730..fe2257f9ac8 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1881,7 +1881,7 @@ 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); |