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Diffstat (limited to 'kernel/futex.c')
-rw-r--r--kernel/futex.c38
1 files changed, 34 insertions, 4 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index f618562b4f5f..0c9850af2724 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -3661,7 +3661,7 @@ static void exit_robust_list(struct task_struct *curr)
}
}
-void futex_exec_release(struct task_struct *tsk)
+static void futex_cleanup(struct task_struct *tsk)
{
if (unlikely(tsk->robust_list)) {
exit_robust_list(tsk);
@@ -3701,7 +3701,7 @@ void futex_exit_recursive(struct task_struct *tsk)
tsk->futex_state = FUTEX_STATE_DEAD;
}
-void futex_exit_release(struct task_struct *tsk)
+static void futex_cleanup_begin(struct task_struct *tsk)
{
/*
* Switch the state to FUTEX_STATE_EXITING under tsk->pi_lock.
@@ -3717,10 +3717,40 @@ void futex_exit_release(struct task_struct *tsk)
raw_spin_lock_irq(&tsk->pi_lock);
tsk->futex_state = FUTEX_STATE_EXITING;
raw_spin_unlock_irq(&tsk->pi_lock);
+}
- futex_exec_release(tsk);
+static void futex_cleanup_end(struct task_struct *tsk, int state)
+{
+ /*
+ * Lockless store. The only side effect is that an observer might
+ * take another loop until it becomes visible.
+ */
+ tsk->futex_state = state;
+}
- tsk->futex_state = FUTEX_STATE_DEAD;
+void futex_exec_release(struct task_struct *tsk)
+{
+ /*
+ * The state handling is done for consistency, but in the case of
+ * exec() there is no way to prevent futher damage as the PID stays
+ * the same. But for the unlikely and arguably buggy case that a
+ * futex is held on exec(), this provides at least as much state
+ * consistency protection which is possible.
+ */
+ futex_cleanup_begin(tsk);
+ futex_cleanup(tsk);
+ /*
+ * Reset the state to FUTEX_STATE_OK. The task is alive and about
+ * exec a new binary.
+ */
+ futex_cleanup_end(tsk, FUTEX_STATE_OK);
+}
+
+void futex_exit_release(struct task_struct *tsk)
+{
+ futex_cleanup_begin(tsk);
+ futex_cleanup(tsk);
+ futex_cleanup_end(tsk, FUTEX_STATE_DEAD);
}
long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,