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Subject[PATCH 4/5] exit: release_task: fix the comment about group leader accounting
Contrary to what the comment in __exit_signal() says we do account the
group leader. Fix this and explain why.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/exit.c | 11 ++++-------
1 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index e0914eb..f773863 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -118,13 +118,10 @@ static void __exit_signal(struct task_struct *tsk)
}

/*
- * Accumulate here the counters for all threads but the group leader
- * as they die, so they can be added into the process-wide totals
- * when those are taken. The group leader stays around as a zombie as
- * long as there are other threads. When it gets reaped, the exit.c
- * code will add its counts into these totals. We won't ever get here
- * for the group leader, since it will have been the last reference on
- * the signal_struct.
+ * Accumulate here the counters for all threads as they die. We could
+ * skip the group leader because it is the last user of signal_struct,
+ * but we want to avoid the race with thread_group_cputime() which can
+ * see the empty ->thread_head list.
*/
task_cputime(tsk, &utime, &stime);
write_seqlock(&sig->stats_lock);
--
1.5.5.1


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