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| author | Michel Lespinasse <walken@google.com> | 2012-11-16 14:14:47 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-11-16 14:33:03 -0800 |
| commit | 63c3b902e517012b127d6528434b928ceaa10f7b (patch) | |
| tree | 7290112c9691492e435ed7ca7912205c3ff10e8c /mm | |
| parent | c5e35d6c512c43105883043dd62cf7257ec3f9f0 (diff) | |
| download | lwn-63c3b902e517012b127d6528434b928ceaa10f7b.tar.gz lwn-63c3b902e517012b127d6528434b928ceaa10f7b.zip | |
mm: add anon_vma_lock to validate_mm()
Iterating over the vma->anon_vma_chain without anon_vma_lock may cause
NULL ptr deref in anon_vma_interval_tree_verify(), because the node in the
chain might have been removed.
BUG: unable to handle kernel paging request at fffffffffffffff0
IP: [<ffffffff8122c29c>] anon_vma_interval_tree_verify+0xc/0xa0
PGD 4e28067 PUD 4e29067 PMD 0
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
CPU 0
Pid: 9050, comm: trinity-child64 Tainted: G W 3.7.0-rc2-next-20121025-sasha-00001-g673f98e-dirty #77
RIP: 0010: anon_vma_interval_tree_verify+0xc/0xa0
Process trinity-child64 (pid: 9050, threadinfo ffff880045f80000, task ffff880048eb0000)
Call Trace:
validate_mm+0x58/0x1e0
vma_adjust+0x635/0x6b0
__split_vma.isra.22+0x161/0x220
split_vma+0x24/0x30
sys_madvise+0x5da/0x7b0
tracesys+0xe1/0xe6
RIP anon_vma_interval_tree_verify+0xc/0xa0
CR2: fffffffffffffff0
Figured out by Bob Liu.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
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/mmap.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 2d942353d681..9a796c41e7d9 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -334,8 +334,10 @@ void validate_mm(struct mm_struct *mm) struct vm_area_struct *vma = mm->mmap; while (vma) { struct anon_vma_chain *avc; + vma_lock_anon_vma(vma); list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) anon_vma_interval_tree_verify(avc); + vma_unlock_anon_vma(vma); vma = vma->vm_next; i++; } |