futex: Provide distinct return value when owner is exiting

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

diff --git a/kernel/futex.c b/kernel/futex.c
index 959af4463c408121f00a4c05a01bfb2dc6a02370..ee6068f96712bc55a245ce506b6f0476aee94e9c 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1182,11 +1182,11 @@ static int handle_exit_race(u32 __user *uaddr, u32 uval,
        u32 uval2;
 
        /*
-        * If the futex exit state is not yet FUTEX_STATE_DEAD, wait
-        * for it to finish.
+        * If the futex exit state is not yet FUTEX_STATE_DEAD, tell the
+        * caller that the alleged owner is busy.
         */
        if (tsk && tsk->futex_state != FUTEX_STATE_DEAD)
-               return -EAGAIN;
+               return -EBUSY;
 
        /*
         * Reread the user space value to handle the following situation:
@@ -2093,12 +2093,13 @@ retry_private:
                        if (!ret)
                                goto retry;
                        goto out;
+               case -EBUSY:
                case -EAGAIN:
                        /*
                         * Two reasons for this:
-                        * - Owner is exiting and we just wait for the
+                        * - EBUSY: Owner is exiting and we just wait for the
                         *   exit to complete.
-                        * - The user space value changed.
+                        * - EAGAIN: The user space value changed.
                         */
                        double_unlock_hb(hb1, hb2);
                        hb_waiters_dec(hb2);
@@ -2859,12 +2860,13 @@ retry_private:
                        goto out_unlock_put_key;
                case -EFAULT:
                        goto uaddr_faulted;
+               case -EBUSY:
                case -EAGAIN:
                        /*
                         * Two reasons for this:
-                        * - Task is exiting and we just wait for the
+                        * - EBUSY: Task is exiting and we just wait for the
                         *   exit to complete.
-                        * - The user space value changed.
+                        * - EAGAIN: The user space value changed.
                         */
                        queue_unlock(hb);
                        put_futex_key(&q.key);