From 4e15eff13fe1baaaef3f94f995b7968ea897f586 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 13 Aug 2019 16:32:35 +0800 Subject: [PATCH] cgroup: Call cgroup_release() before __exit_signal() commit 6b115bf58e6f013ca75e7115aabcbd56c20ff31d upstream. cgroup_release() calls cgroup_subsys->release() which is used by the pids controller to uncharge its pid. We want to use it to manage iteration of dying tasks which requires putting it before __unhash_process(). Move cgroup_release() above __exit_signal(). While this makes it uncharge before the pid is freed, pid is RCU freed anyway and the window is very narrow. Signed-off-by: Tejun Heo Cc: Oleg Nesterov Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yang Yingliang --- kernel/exit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/exit.c b/kernel/exit.c index 936333b9f25b..a8a4cea2119b 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -194,6 +194,7 @@ void release_task(struct task_struct *p) rcu_read_unlock(); proc_flush_task(p); + cgroup_release(p); write_lock_irq(&tasklist_lock); ptrace_release_task(p); @@ -219,7 +220,6 @@ void release_task(struct task_struct *p) } write_unlock_irq(&tasklist_lock); - cgroup_release(p); release_thread(p); call_rcu(&p->rcu, delayed_put_task_struct); -- GitLab