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| author | Carsten Otte <cotte@de.ibm.com> | 2009-02-04 15:12:16 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-02-05 12:56:48 -0800 |
| commit | ab92661d5d9514647346047f30f67a7f35ffea67 (patch) | |
| tree | 3ed67a71d7cce6dbd5b6bd559966f7fc137c8f00 /mm | |
| parent | 777c6c5f1f6e757ae49ecca2ed72d6b1f523c007 (diff) | |
| download | linux-ab92661d5d9514647346047f30f67a7f35ffea67.tar.gz linux-ab92661d5d9514647346047f30f67a7f35ffea67.tar.bz2 linux-ab92661d5d9514647346047f30f67a7f35ffea67.zip | |
do_wp_page: fix regression with execute in place
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>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 22bfa7a47a0b..baa999e87cd2 100644 --- a/mm/memory.c +++ b/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); |