[PATCH 08/31] restore the DEATH/REAP utrace hooks
Restore the necessary hooks in release_task() and exit_notify(),
add the corresponding helpers into utrace.h.
Note: the @signal argument passed to ->report_death() does not
match the previous behaviour. I think this shouldn't affect the
current users, and I bet nobody can really understand what this
magic argument should actually mean anyway.
Signed-off-by: Oleg Nesterov <oleg(a)redhat.com>
---
include/linux/utrace.h | 22 ++++++++++++++++++++++
kernel/exit.c | 4 ++++
2 files changed, 26 insertions(+), 0 deletions(-)
diff --git a/include/linux/utrace.h b/include/linux/utrace.h
index 9a2e2f4..cf13839 100644
--- a/include/linux/utrace.h
+++ b/include/linux/utrace.h
@@ -697,4 +697,26 @@ static inline __must_check int utrace_barrier_pid(struct pid *pid,
#endif /* CONFIG_UTRACE */
+static inline void utrace_release_task(struct task_struct *task)
+{
+ /* see utrace_add_engine() about this barrier */
+ smp_mb();
+ if (task_utrace_flags(task))
+ utrace_maybe_reap(task, task_utrace_struct(task), true);
+}
+
+static inline void utrace_exit_notify(struct task_struct *task,
+ int signal, int group_dead)
+{
+ /*
+ * If utrace_set_events() was just called to enable
+ * UTRACE_EVENT(DEATH), then we are obliged to call
+ * utrace_report_death() and not miss it. utrace_set_events()
+ * checks @task->exit_state under tasklist_lock to synchronize
+ * with exit_notify(), the caller.
+ */
+ if (task_utrace_flags(task) & _UTRACE_DEATH_EVENTS)
+ utrace_report_death(task, group_dead, signal);
+}
+
#endif /* linux/utrace.h */
diff --git a/kernel/exit.c b/kernel/exit.c
index c1b0ab6..ba5ba22 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -168,6 +168,8 @@ void release_task(struct task_struct * p)
struct task_struct *leader;
int zap_leader;
repeat:
+ utrace_release_task(p);
+
/* don't need to get the RCU readlock here - the process is dead and
* can't be modifying its own credentials. But shut RCU-lockdep up */
rcu_read_lock();
@@ -860,6 +862,8 @@ static void exit_notify(struct task_struct *tsk, int group_dead)
wake_up_process(tsk->signal->group_exit_task);
write_unlock_irq(&tasklist_lock);
+ utrace_exit_notify(tsk, autoreap ? -1 : SIGCHLD, group_dead);
+
/* If the process is dead, release it - nobody will wait for it */
if (autoreap)
release_task(tsk);
--
1.5.5.1