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authorMichel Lespinasse <walken@google.com>2012-11-16 14:14:47 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-11-16 14:33:03 -0800
commit63c3b902e517012b127d6528434b928ceaa10f7b (patch)
parentc5e35d6c512c43105883043dd62cf7257ec3f9f0 (diff)
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>
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)
+ vma_unlock_anon_vma(vma);
vma = vma->vm_next;