1 files changed, 21 insertions, 16 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index dbf571547c03..11b23f203d68 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -329,23 +329,26 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
          * with it
          */
 retry:
-        lock_page_cgroup(page);
-        pc = page_get_page_cgroup(page);
-        /*
-         * The page_cgroup exists and the page has already been accounted
-         */
-        if (pc) {
-                if (unlikely(!atomic_inc_not_zero(&pc->ref_cnt))) {
-                        /* this page is under being uncharged ? */
-                        unlock_page_cgroup(page);
-                        cpu_relax();
-                        goto retry;
-                } else {
-                        unlock_page_cgroup(page);
-                        goto done;
+        if (page) {
+                lock_page_cgroup(page);
+                pc = page_get_page_cgroup(page);
+                /*
+                 * The page_cgroup exists and
+                 * the page has already been accounted.
+                 */
+                if (pc) {
+                        if (unlikely(!atomic_inc_not_zero(&pc->ref_cnt))) {
+                                /* this page is under being uncharged ? */
+                                unlock_page_cgroup(page);
+                                cpu_relax();
+                                goto retry;
+                        } else {
+                                unlock_page_cgroup(page);
+                                goto done;
+                        }
                 }
+                unlock_page_cgroup(page);
         }
-        unlock_page_cgroup(page);
 
         pc = kzalloc(sizeof(struct page_cgroup), gfp_mask);
         if (pc == NULL)
@@ -404,7 +407,7 @@ retry:
         if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
                 pc->flags |= PAGE_CGROUP_FLAG_CACHE;
 
-        if (page_cgroup_assign_new_page_cgroup(page, pc)) {
+        if (!page || page_cgroup_assign_new_page_cgroup(page, pc)) {
                 /*
                  * Another charge has been added to this page already.
                  * We take lock_page_cgroup(page) again and read
@@ -413,6 +416,8 @@ retry:
                 res_counter_uncharge(&mem->res, PAGE_SIZE);
                 css_put(&mem->css);
                 kfree(pc);
+                if (!page)
+                        goto done;
                 goto retry;
         }