ptrace: use fsuid, fsgid, effective creds for fs access checks

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / mm / rmap.c

diff --git a/mm/rmap.c b/mm/rmap.c
index 6280da86b5d6761ed8a245c3fadb6e42015216c5..705bfc8e6fcdd2059f815edf6bcd892a6cfe0630 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 */
@@ -600,7 +602,11 @@ pte_t *__page_check_address(struct page *page, struct mm_struct *mm,
        spinlock_t *ptl;
 
        if (unlikely(PageHuge(page))) {
+               /* when pud is not present, pte will be NULL */
                pte = huge_pte_offset(mm, address);
+               if (!pte)
+                       return NULL;
+
                ptl = &mm->page_table_lock;
                goto check;
        }
@@ -1386,9 +1392,19 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
                BUG_ON(!page || PageAnon(page));
 
                if (locked_vma) {
-                       mlock_vma_page(page);   /* no-op if already mlocked */
-                       if (page == check_page)
+                       if (page == check_page) {
+                               /* we know we have check_page locked */
+                               mlock_vma_page(page);
                                ret = SWAP_MLOCK;
+                       } else if (trylock_page(page)) {
+                               /*
+                                * If we can lock the page, perform mlock.
+                                * Otherwise leave the page alone, it will be
+                                * eventually encountered again later.
+                                */
+                               mlock_vma_page(page);
+                               unlock_page(page);
+                       }
                        continue;       /* don't unmap */
                }
 
@@ -1661,10 +1677,9 @@ 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);
 }
 
 #ifdef CONFIG_MIGRATION