mm: migrate: Close race between migration completion and mprotect

[platform/adaptation/renesas_rcar/renesas_kernel.git] / mm / rmap.c

diff --git a/mm/rmap.c b/mm/rmap.c
index d3cbac5..cdbd312 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -103,6 +103,7 @@ static inline void anon_vma_free(struct anon_vma *anon_vma)
         * LOCK should suffice since the actual taking of the lock must
         * happen _before_ what follows.
         */
+       might_sleep();
        if (rwsem_is_locked(&anon_vma->root->rwsem)) {
                anon_vma_lock_write(anon_vma);
                anon_vma_unlock_write(anon_vma);
@@ -426,8 +427,9 @@ struct anon_vma *page_get_anon_vma(struct page *page)
         * above cannot corrupt).
         */
        if (!page_mapped(page)) {
+               rcu_read_unlock();
                put_anon_vma(anon_vma);
-               anon_vma = NULL;
+               return NULL;
        }
 out:
        rcu_read_unlock();
@@ -477,9 +479,9 @@ struct anon_vma *page_lock_anon_vma_read(struct page *page)
        }
 
        if (!page_mapped(page)) {
+               rcu_read_unlock();
                put_anon_vma(anon_vma);
-               anon_vma = NULL;
-               goto out;
+               return NULL;
        }
 
        /* we pinned the anon_vma, its safe to sleep */
@@ -1554,10 +1556,9 @@ void __put_anon_vma(struct anon_vma *anon_vma)
 {
        struct anon_vma *root = anon_vma->root;
 
+       anon_vma_free(anon_vma);
        if (root != anon_vma && atomic_dec_and_test(&root->refcount))
                anon_vma_free(root);
-
-       anon_vma_free(anon_vma);
 }
 
 static struct anon_vma *rmap_walk_anon_lock(struct page *page,