Merge branch 'master' into for-next

Sync with Linus' tree to be able to apply pending patches that
are based on newer code already present upstream.

1 files changed, 15 insertions, 16 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 07dc154fc799..14c9b63a96c3 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -560,29 +560,28 @@ void exit_files(struct task_struct *tsk)
 
 #ifdef CONFIG_MM_OWNER
 /*
- * Task p is exiting and it owned mm, lets find a new owner for it
+ * A task is exiting.   If it owned this mm, find a new owner for the mm.
  */
-static inline int
-mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
-{
-        /*
-         * If there are other users of the mm and the owner (us) is exiting
-         * we need to find a new owner to take on the responsibility.
-         */
-        if (atomic_read(&mm->mm_users) <= 1)
-                return 0;
-        if (mm->owner != p)
-                return 0;
-        return 1;
-}
-
 void mm_update_next_owner(struct mm_struct *mm)
 {
         struct task_struct *c, *g, *p = current;
 
 retry:
-        if (!mm_need_new_owner(mm, p))
+        /*
+         * If the exiting or execing task is not the owner, it's
+         * someone else's problem.
+         */
+        if (mm->owner != p)
                 return;
+        /*
+         * The current owner is exiting/execing and there are no other
+         * candidates.  Do not leave the mm pointing to a possibly
+         * freed task structure.
+         */
+        if (atomic_read(&mm->mm_users) <= 1) {
+                mm->owner = NULL;
+                return;
+        }
 
         read_lock(&tasklist_lock);
         /*