rmap: always add new vmas at the end
Make sure to always add new VMAs at the end of the list. This is
important so rmap_walk does not miss a VMA that was created during the
rmap_walk.
The old code got this right most of the time due to luck, but was buggy
when anon_vma_prepare reused a mergeable anon_vma.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-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>
diff --git a/mm/rmap.c b/mm/rmap.c
index 07e9814..dce74a9 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -147,7 +147,7 @@
avc->anon_vma = anon_vma;
avc->vma = vma;
list_add(&avc->same_vma, &vma->anon_vma_chain);
- list_add(&avc->same_anon_vma, &anon_vma->head);
+ list_add_tail(&avc->same_anon_vma, &anon_vma->head);
allocated = NULL;
avc = NULL;
}