mm: rmap: explicitly reset vma->anon_vma in unlink_anon_vmas()

[linux-2.6-microblaze.git] / mm / rmap.c

diff --git a/mm/rmap.c b/mm/rmap.c
index 5ebf16f..e26ae11 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -413,8 +413,15 @@ void unlink_anon_vmas(struct vm_area_struct *vma)
                list_del(&avc->same_vma);
                anon_vma_chain_free(avc);
        }
-       if (vma->anon_vma)
+       if (vma->anon_vma) {
                vma->anon_vma->degree--;
+
+               /*
+                * vma would still be needed after unlink, and anon_vma will be prepared
+                * when handle fault.
+                */
+               vma->anon_vma = NULL;
+       }
        unlock_anon_vma_root(root);
 
        /*