futex: Replace PF_EXITPIDONE with a state

[mirror_ubuntu-bionic-kernel.git] / kernel / futex.c

diff --git a/kernel/futex.c b/kernel/futex.c
index 2bec1627075372e816664f85e6b0325dbaf3096f..10c75096d601c1dbb78d2e951c9856523b7bcffe 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1182,9 +1182,10 @@ static int handle_exit_race(u32 __user *uaddr, u32 uval,
        u32 uval2;
 
        /*
-        * If PF_EXITPIDONE is not yet set, then try again.
+        * If the futex exit state is not yet FUTEX_STATE_DEAD, wait
+        * for it to finish.
         */
-       if (tsk && !(tsk->flags & PF_EXITPIDONE))
+       if (tsk && tsk->futex_state != FUTEX_STATE_DEAD)
                return -EAGAIN;
 
        /*
@@ -1203,8 +1204,9 @@ static int handle_exit_race(u32 __user *uaddr, u32 uval,
         *    *uaddr = 0xC0000000;           tsk = get_task(PID);
         *   }                               if (!tsk->flags & PF_EXITING) {
         *  ...                                attach();
-        *  tsk->flags |= PF_EXITPIDONE;     } else {
-        *                                     if (!(tsk->flags & PF_EXITPIDONE))
+        *  tsk->futex_state =               } else {
+        *      FUTEX_STATE_DEAD;              if (tsk->futex_state !=
+        *                                        FUTEX_STATE_DEAD)
         *                                       return -EAGAIN;
         *                                     return -ESRCH; <--- FAIL
         *                                   }
@@ -1260,17 +1262,16 @@ static int attach_to_pi_owner(u32 __user *uaddr, u32 uval, union futex_key *key,
        }
 
        /*
-        * We need to look at the task state flags to figure out,
-        * whether the task is exiting. To protect against the do_exit
-        * change of the task flags, we do this protected by
-        * p->pi_lock:
+        * We need to look at the task state to figure out, whether the
+        * task is exiting. To protect against the change of the task state
+        * in futex_exit_release(), we do this protected by p->pi_lock:
         */
        raw_spin_lock_irq(&p->pi_lock);
-       if (unlikely(p->flags & PF_EXITING)) {
+       if (unlikely(p->futex_state != FUTEX_STATE_OK)) {
                /*
-                * The task is on the way out. When PF_EXITPIDONE is
-                * set, we know that the task has finished the
-                * cleanup:
+                * The task is on the way out. When the futex state is
+                * FUTEX_STATE_DEAD, we know that the task has finished
+                * the cleanup:
                 */
                int ret = handle_exit_race(uaddr, uval, p);