[PATCH 1/3] de_thread: mt-exec should update ->real_start_time

[Oleg Nesterov <oleg@redhat.com>]

924b42d5 "Use boot based time for process start time and boot
time in /proc" updated copy_process/do_task_stat but forgot
about de_thread(). This breaks "ps axOT" if a sub-thread execs.

Note: I think that task->start_time should die.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 fs/exec.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index 00eaba7..aeace12 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -930,6 +930,7 @@ static int de_thread(struct task_struct *tsk)
 		 * also take its birthdate (always earlier than our own).
 		 */
 		tsk->start_time = leader->start_time;
+		tsk->real_start_time = leader->real_start_time;
 
 		BUG_ON(!same_thread_group(leader, tsk));
 		BUG_ON(has_group_leader_pid(tsk));
-- 
1.5.5.1