1 files changed, 23 insertions, 1 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 5b888c24e43e..5c8ecbaa19a5 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -892,13 +892,29 @@ fastcall NORET_TYPE void do_exit(long code)
         if (unlikely(tsk->flags & PF_EXITING)) {
                 printk(KERN_ALERT
                         "Fixing recursive fault but reboot is needed!\n");
+                /*
+                 * We can do this unlocked here. The futex code uses
+                 * this flag just to verify whether the pi state
+                 * cleanup has been done or not. In the worst case it
+                 * loops once more. We pretend that the cleanup was
+                 * done as there is no way to return. Either the
+                 * OWNER_DIED bit is set by now or we push the blocked
+                 * task into the wait for ever nirwana as well.
+                 */
+                tsk->flags |= PF_EXITPIDONE;
                 if (tsk->io_context)
                         exit_io_context();
                 set_current_state(TASK_UNINTERRUPTIBLE);
                 schedule();
         }
 
+        /*
+         * tsk->flags are checked in the futex code to protect against
+         * an exiting task cleaning up the robust pi futexes.
+         */
+        spin_lock_irq(&tsk->pi_lock);
         tsk->flags |= PF_EXITING;
+        spin_unlock_irq(&tsk->pi_lock);
 
         if (unlikely(in_atomic()))
                 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
@@ -912,7 +928,7 @@ fastcall NORET_TYPE void do_exit(long code)
         }
         group_dead = atomic_dec_and_test(&tsk->signal->live);
         if (group_dead) {
-                hrtimer_cancel(&tsk->signal->real_timer);
+                hrtimer_cancel(&tsk->signal->real_timer);
                 exit_itimers(tsk->signal);
         }
         acct_collect(code, group_dead);
@@ -965,6 +981,12 @@ fastcall NORET_TYPE void do_exit(long code)
          * Make sure we are holding no locks:
          */
         debug_check_no_locks_held(tsk);
+        /*
+         * We can do this unlocked here. The futex code uses this flag
+         * just to verify whether the pi state cleanup has been done
+         * or not. In the worst case it loops once more.
+         */
+        tsk->flags |= PF_EXITPIDONE;
 
         if (tsk->io_context)
                 exit_io_context();